WO2010149999A1

WO2010149999A1 - Wrench

Info

Publication number: WO2010149999A1
Application number: PCT/GB2010/051012
Authority: WO
Inventors: John Mann
Original assignee: Fielding, Craig
Priority date: 2009-06-25
Filing date: 2010-06-18
Publication date: 2010-12-29
Also published as: GB201122280D0; GB2483598A; GB0910996D0

Abstract

The invention relates to a wrench (1) which supports an insert (30), the insert (30) being capable of engaging a nut. The insert (30) is exchangeable for another insert (30) to allow the wrench (1) to engage various sizes of nuts. The wrench (1) comprises a handle (10); a head (20) attached to the handle (10); a mouth (21) within the head (20); and an insert (30) within the mouth (21); wherein the insert (30) is slidably removable from the mouth (21) and the insert (30) comprises an open-ended and/or closed-ring nut-engagement portion (31).

Description

Wrench

The present invention relates to a wrench. In particular the invention relates to a wrench which supports an insert, the insert being capable of engaging a nut. More particularly the invention relates to a wrench where the insert is exchangeable for another insert to allow the wrench to engage various sizes of nuts. The present invention also relates to an insert, a wrench head, a kit of inserts, a wrench kit, and a method of operating upon a nut.

Common wrenches, typically of the open-ended or closed-ring type, are widely used by engineers and mechanics for tightening and loosening nuts and the like. Since each individual wrench has its own particular size, large and heavy tool boxes are required to transport a kit of the wrenches. This can lead to portability problems, especially in hostile environments such as those experienced by military engineers. As such, spare wrenches are unlikely to be carried in such environments, thus increasing any adverse impact when a wrench is lost. Such wrenches are also relatively costly to manufacture since each differently sized wrench has a different handle as well as a different wrench head. This means that wrenches are costly to replace when lost or broken. Indeed, such wrenches often suffer after repeated use at high torques as the jaws are prone to splay. Finally, the bulkiness of each individual wrench means a large space is required to exhibit wrenches in shop displays.

A possible solution to some of these problems is the widely used socket wrench which receives a range of sizes of interchangeable sockets. Sockets, typically of the 6-point or 12- point recess variety, slot into/onto the wrench via a top face, usually over a protruding square fitting which is itself optionally connected to a ratchet mechanism. They are then usable to tighten or loosen nuts in the usual fashion. A problem with such wrenches is that the sockets are sometimes difficult to handle, are easy to lose, and can roll around owing to their cylindrical shape. The sockets are difficult to stack in shop displays, and usually have to be secured in boxes or packaging of a relatively intricate design in order to prevent the sockets rolling around. Moreover, being top-face loaded, sockets are sometime awkward to remove from and install onto a wrench, and can be easily dropped under conditions of reduced dexterity and vision. Finally, high torques can take their toll on sockets, leaving them damaged so that they slip around nuts.

It is an object of the present invention to solve at least one of the problems of the prior art.

According to a first aspect of the present invention, there is provided a wrench comprising a handle; a head attached to the handle; a mouth within the head; and an insert within the mouth; wherein the insert is slidably removable from the mouth and the insert comprises an open-ended and/or closed-ring nut-engagement portion. The nut-engagement portion is preferably arranged to engage a nut.

The wrench has the advantage that only a single wrench is needed to accommodate a range of nut sizes. This means a kit containing a wrench with several inserts is very portable. Moreover, spare inserts can be carried without impairing portability. The kit is relatively simple and cheap to manufacture, as only a single wrench is needed. An insert for each nut size is also much cheaper to produce than a whole wrench for each nut size. Moreover, shop displays of a range of inserts can be space efficient.

The fact that the insert sits within the mouth means the mouth dissipates torsional forces and stress around the head and, in so doing, avoids stress at joints and reduces ware and/or distortion of any nut-engagement portions.

Herein the term "nut" is intended to mean a turnable element, preferably a polygonal turnable element. The polygonal turnable element may be shaped as a regular polygon. The turnable element may itself threaded (e.g. a standard nut such as a hex nut), preferably internally threaded. Alternatively, the turnable element may be connected to a threaded piece (eg. a standard bolt), preferably externally threaded. Preferably the turnable element is hexagonal, but may also be square, diamond, pentagonal, octagonal, dodecahedral, etc. Furthermore, the term "nut" may encompass bolts with nut-shaped ends (polygonal-shaped ends), and/or other forms of fasteners which can be engaged by a wrench, e.g. acorn nuts, socket head cap screw, cleveloc nuts, and also turnable elements of pipework.

Preferably, the "nut" with which the nut-engagement portion is arranged to engage has an effective nut radius of a maximum of 4 centimetres (cm), more preferably a maximum of 2.6 cm, and most preferably a maximum of 1.3 cm. Where the nut is shaped as a regular polygon, the effective nut radius is measured from the centre of the "nut" to a central point along an outer edge of a polygonal side (i.e. where a radial line from the centre of the nut intersects the outer edge at a right angle).

The nut-engagement portion may be arranged to engage a nut of irregular shape. "Irregular" preferably means a shape where two or more sides of the shape have different lengths to each other. "Irregular" may mean an asymmetric shape. The nut of irregular shape may thus be a security nut which cannot be engaged by a standard wrench. Such nuts may be used to lock water hydrants, gas hydrants, lamp posts, and the like, so as to restrict access thereto. As such the nut may be a lock member, and the nut-engagement portion may be a complementary key to the lock member. Where the nut-engagement portion is arranged to engage a nut of irregular shape, the effective nut radius is taken to be half the longest possible length measured across the nut (this may be edge to edge or point to point).

The insert is preferably substantially flat. This makes the inserts much easier to handle compared to cylindrical sockets which can be easy to lose, particularly as such sockets can roll away. Moreover, inserts of the present invention are easy to stack, facilitating storage, packaging, and displaying in shops.

Herein a "socket" relates to a socket wrench and is generally intended to mean a substantially cylindrical element which can engage a nut by virtue of a closed-ring nut-engagement portion.

The insert is preferably usable on its own (without the wrench or head) to turn loose nuts. This allows a nut to be tightened onto a bolt before the wrench, or head of the wrench, is slid onto the insert ready for a final tightening of the nut. Alternatively, it allows a nut to be initially loosened with the wrench in place, before the wrench is removed from the insert, and the insert is used to perform the remainder of the loosening. Such slidable removability of inserts from the head, whilst the nut-engagement portion is still engaged with a nut, allows open- ended wrenches to be used in this way. Such slidable removal is also an advantage for close- ringed nut-engagement portions since slidably removing the wrench will not cause the nut- engagement portion to dislocate from the nut, whereas sockets of socket wrenches can easily detach from a nut as the wrench is pulled away from the socket.

Moreover, a wrench capable of receiving an insert slidably from the side, rather than from a tap face, is much less fiddly and allows for facile swapping of inserts. In fact, inserts of the present invention can be easily interchanged in conditions of poor visibility.

The mouth preferably has at least one internal wall. Preferably the mouth has two internal walls. Preferably the two internal walls are connected by a cross member or throat. In this case the mouth has an exit (or opening) and a throat. Preferably the two internal walls are parallel or substantially parallel. Preferably the mouth is substantially square. This allows it to accommodate a square insert such that the insert fills the mouth (i.e. there are no gaps).

The position of the mouth relative to the head is preferably permanently fixed. Therefore, the head preferably does not comprise a ratchet mechanism. A ratchet mechanism makes it difficult to detach the head from the insert whilst leaving the insert still engaged with a nut. This is because the mouth is not in a position to allow an insert to be removed when intermediate ratchet positions are adopted, i.e. the mouth turns into the head. Moreover, insertion/removal of an insert is less fiddly without a ratchet mechanism, and inserts are less likely to be lost/dropped. Furthermore, the robustness of the lock mechanism is greater when a ratchet mechanism is absent within the head. However, a ratchet mechanism may exist between the handle and the head as this would not interfere with the functionality of the insert.

The insert preferably comprises two faces, which are preferably substantially flat surfaces. Each face is preferably visible when the insert is held within the mouth. The insert preferably comprises a plurality of external edges, wherein at least one edge preferably comprises either a recess or a Np, which recess or lip is arranged to slidably engage an internal wall of the mouth. The internal wall of the mouth therefore preferably comprises a lip or a recess to complement the insert. Preferably the insert comprises four external edges (excluding internal edges characterised by such as an open-ended nut-engagement portion). Preferably at least two external edges comprise either a recess or lip to compliment slidable fitting within the mouth. All external edges may comprise a complementary recess or lip. The insert may comprise one external edge with a lip, and another external edge with a recess, and the mouth may comprise a recess in one internal wall and a lip on another internal wall to complement the insert.

The insert preferably has an exposed external edge (exposed when within the mouth) which is substantially flush with an edge of the head at the exit of the mouth. This makes for a neater appearance, easier storage, and easier engagement with nuts with limited accessibility. Moreover, this arrangement maximises dissipation of any torsional stress, incurred when operating on a nut, throughout the head.

The insert preferably has a thickness substantially the same as the thickness of the head at the mouth. This maximises dissipation of torsional stress through the head, and creates a substantially flat wrench head meaning nuts are more easily engaged, and the wrench cannot inconveniently catch on other items.

The insert preferably comprises at least two nut-engagement portions. It may comprise three nut-engagement portions or more. Preferably the insert comprises a maximum of four nut- engagement portions. Preferably each nut-engagement portion is associated with a distinct external edge of the insert, thus allowing the insert to be simply rotated within the mouth to bring another nut-engagement portion into use.

Preferably, one of the at least two nut-engagement portions is open-ended. Preferably one of the at least two nut-engagement portions is closed-ring. Most preferably the insert comprises both open-ended and closed-ring nut-engagement portions. Having the facility for two types of nut-engagement portion (e.g. both open-ended and closed-ring) in a single insert is highly convenient. One or other of the nut-engagement portions can be brought into use by simply removing the insert, rotating it, and reinserting it into the mouth. However, the nut- engagement portion most distal from the exit of the mouth (i.e. near a throat) may still be usable without rotating the insert. The insert may comprise a number of nut-engagement portions of different sizes and/or types, thus increasing the functionality of a simple insert, and again reducing overall weight and bulk of a kit of inserts.

The insert is preferably rearrangeable to adopt at least one alternative orientation within the mouth. This increases the functionality of each insert.

Preferably the wrench comprises a lock mechanism for releasably locking the insert within the mouth. Preferably the head comprises part or all of the lock mechanism. Preferably, the insert can be locked in at least one alternative orientation within the mouth. This insert may comprise a lock receiver in the edge for the lock mechanism to engage. The insert may comprise a lock receiver in two or more of the external edges.

The insert is preferably a single solid piece. Preferably, the mouth only accommodates a single insert. Preferably the size of a nut-engagement portion is not reducable by adding an additional insert. This creates weakness within the wrench when operating upon a nut, and inserts wear down as they grate against each other.

The handle is preferably attached to the head at a handle attachment point. The head preferably comprises head edges, including a base and at least one side. Preferably the handle is attached to the base of the head. The handle is preferably removably attached to the head. This allows a new head to be attached, which head is a different size and designed to accommodate a different range of inserts. Alternatively, the handle may be permanently fixed to the head. This provides a more robust joint between the handle and the head.

The head is preferably rearrangable to adopt at least one alternative orientation relative to the handle. The head may have at least two handle attachment points. Preferably the head can be attached to the handle at two different edges of the head. The head may have one handle attachment point on the base and another on the side.

The head preferably comprises a handle attachment point, which allows the handle to meet the head at a plurality of angles relative to a head edge. Preferably the handle is arrangeable to be substantially perpendicular to the head edge or inclined from perpendicular. Preferably the incline is less than 30° from perpendicular, more preferably less than 20° and most preferably less than 10° from perpendicular. Such an incline facilitates the application of greater torque when operating upon a nut. Alternatively, the handle may be fixed at a single angle, preferably perpendicular to the head edge (or base). In this case, the handle attachment point would not allow for a plurality of angles between the handle and the head edge (or base).

The handle may be extendible and/or retractable. Preferably the handle is lockable in a plurality of extended or retracted positions.

The handle may be attached to the head via a ratchet mechanism. This can provide some of the benefits of a ratchet mechanism without the disadvantages discussed above.

The shape of the perimeter of the insert is preferably substantially different form the shape of the nut-engagement portion. This disrupts coherent transmission of torsional strain to the head, thus rendering the wrench and its component parts more resistant to wear or distortion.

The insert may comprise a socket receiver for receiving sockets. This socket receiver may be a standard square fitting, protruding from one of the faces of the insert.

In accordance with a second aspect of the present invention there is provided a wrench head for a wrench, the head comprising a mouth arranged to slidably receive an insert having an open-ended and/or closed-ring nut-engagement portion.

Preferably a volume ratio of the mouth to the head (which includes the mouth) is between 0.15:1 and 0.4:1. A ratio of facial surface areas of the mouth to the head (which includes the mouth) is preferably between 0.15:1 and 0.4:1.

According to a third aspect of the present invention there is provided an insert, which insert is slidably insertable and slidably removable from a mouth of a head of a wrench, the insert comprising an open-ended and/or closed-ring nut-engagement portion.

A visible front face of the insert may be defined as a visible part of one of the faces of the insert when the insert is fully contained within the mouth, i.e. this excludes any lips which allow inserts to fit within the mouth. The visible front face preferably has a ratio of surface areas of solid portion to the empty nut-engagement portion(s) of at least 1 :3.5, more preferably at least 1.5:1 , and preferably a ratio of at most 46:1 , more preferably at most 11 :1. This ensures the insert is always strong and durable when used at high torques with wrenches according to the first aspect. Where there is more than one nut-engagement portion within the insert, the surface area of the empty nut-engagement portion(s) is the total empty space. Where there is an open-ended nut-engagement portion, the empty space is calculated up to a hypothetic edge of the insert, which edge would be present if the nut-engagement portion was not open- ended.

The nut-engagement portion has a diameter, preferably defined by the diameter of the nut the nut-engagement portion is arranged to engage. The diameter is therefore typically twice the effective nut radius. Where the nut-engagement portion is arranged to engage a nut of regular polygonal shape, the diameter is defined by a shortest distance between two opposite sides of the nut-engagement portion. Where the nut-engagement portion is arranged to engage a nut of irregular shape, the diameter is twice the effective nut radius as described above. The insert also comprises an outer portion (generally to each side of the nut-engagement portion), the width of which is a shortest distance between the nut-engagement portion and an external edge of the insert (excluding any lip). The ratio of the diameter of the nut-engagement portion to the width of the outer portion of the insert is preferably at least 1 :4.5, more preferably at least 1 :2, and most preferably at least 1 : 1.6. The ratio of the diameter of the nut-engagement portion to the width of the outer portion is preferably at most 3:1 , more preferably at most 2:1 , and most preferably at most 1.33:1.

According to a fourth aspect of the present invention, there is provided a kit of inserts comprising a plurality of inserts.

According to a fifth aspect of the present invention, there is provided a wrench kit comprising a handle, a head either attached or removably attached to the handle, and a plurality of inserts.

According to a sixth aspect of the present invention, there is provided a method of operating upon a nut, comprising the steps of a) slidably inserting an insert into the mouth of the head of the wrench, b) engaging the nut with a nut-engagement portion of the insert, and c) turning the nut.

Preferred features of any aspect of the present invention are also preferred features in relation to any other aspect, particularly with respect to the insert and head.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which:

Figure 1 is a plan view of a wrench;

Figure 2 is a perspective view of the wrench of Figure 1 ; Figure 3 is a perspective view of the wrench of Figure 2, but with an insert rotated 180°;

Figure 4 is a plan view of the wrench of Figure 1 , but with a head rotated 90°;

Figure 5 is a plan view of the wrench of Figure 1 , with a handle adjusted;

Figure 6 is a perspective view of an insert;

Figure 7 is a perspective view of the insert of Figure 6 rotated 180°;

Figure 8 is a perspective view of an alternative embodiment of the insert;

Figure 9 is a perspective view of a head of the wrench of Figure 1 ; and

Figure 10 is a perspective view of the head of Figure 9 rotated 180°.

The exemplary embodiments of the present invention will now be discussed in detail in relation to a wrench which can interchangably accommodate a variety of inserts to adapt the wrench for engagement with variously sized nuts. However, the teachings, principles and techniques of the present invention are also applicable in other exemplary embodiments.

Figure 1 shows a plan view of a wrench 1 having a handle 10 attached to a head 20. The head accommodates an insert 30 within a mouth 21 within the head. The mouth is generally U-shaped (in this case a squared U-shape), having two parallel internal walls 21a connected across respective ends by a cross member 21 b (or throat).

The handle 10 is attached to the head 20 at a handle attachment point 22 located upon a base 20c of the head 20. The head has a lock 40 located on a side 20b of the head 20 for securing the insert 30 in place within the mouth 21.

In this example, the insert has two nut-engagement portions 31 , an open-ended nut- engagement portion 31a and a closed-ring nut-engagement portion 31 b. The insert 30 also has a visible face 32 on either side of the wrench 1 , and four external edges 33. In this example, one of the external edges 33 is an exposed external edge 33a, whereas three of the edges 33 are unexposed external edges 33b. In this case, the exposed external edge 33a is flush with a mouth edge 20a of the head 20. Moreover, both the insert 30 and the head 20 are essentially flat. In this example the insert has a length (as measured from an exit of the mouth to a throat of the mouth) of 5 cm and a width (as measured from one side wall of the mouth to the other side wall of the mouth) of 4.5 cm. The insert has a thickness of 1.75 cm. Both the open-ended and closed-ring nut-engagement portions 31a and 31 b have a diameter (d) defined by a shortest distance between two opposite sides of the nut-engagement portion, which in this example is 2 cm for both nut-engagement portions. Moreover, the insert has an outer portion 30a, the width (w) of which is a shortest distance between the nut-engagement portion and an external edge of the insert (excluding any lip), and is in this example 1.5 cm. The ratio of the diameter (d) to the width (w), in this example is therefore 1.33:1. For this insert, a ratio of surface areas of solid portions to empty nut-engagement portions is about 1.9:1.

Figure 2 shows a perspective view of the wrench 1. This shows how the insert 30 fits within the mouth 21 by virtue of lips 34 around the two unexposed external edges 33b of the insert 30, and recesses 23 within internal walls 21a of the mouth 21. In this example, the lips 34 slide neatly into the recesses 23. In alternative embodiments, the arrangement of lips and recesses can be reversed so that the internal walls 21a of the mouth 21 have lips and the external edges of the inserts have recesses.

Figure 3 also shows a perspective view of the wrench 1 , but with the insert 30 rotated 180° so that the closed-ring nut-engagement portion 131 b is towards an exit of the mouth 25 (see Figure 10). This is simply achieved by removing the insert 30 from the wrench 1 of Figure 1 and slidably reinserting it the other way round.

Figure 4 shows a plan view of the wrench 1. Two handle attachment points 22 are shown upon the head 20, one upon the base 20c and one on the side 20b. Figure 4 differs from Figure 1 in that the handle is now attached to the side 20b of the head 20 rather than the base 20c. Each handle attachment point 22 can be a simple threaded screw attachment, with a complimenting screw thread at an end of the handle 10.

Figure 5 shows a plan view of the wrench 1. Here the handle 10 is attached to the base 20c of the head 20, as per Figure 1 , but the handle has been inclined relative to the base 20c by an angle of 15°. In this embodiment the handle attachment point 22 is in the form of a lockable ratchet, allowing the handle to be selectively inclined and locked in position. Such a ratchet mechanism can serve a dual purpose as it first allows for this incline, and also allows handle adjustment whilst a nut is being tightened, thus providing greater torque for a final twist.

Figures 6 and 7 show a perspective view of the insert 30, and show a lock receiver 35 in two of the unexposed external edges 33b of the insert 30. The lock receiver 35 is arranged to receive the lock 40, which, in this example is in the form of a pin or a rod. The lock receiver 35 in this example, is a recess in one of the unexposed external edges 33b, and gives rise to a gap in the lip 34. The position of the lock receiver on each unexposed external edge 33b allows the insert to be locked within the mouth 21 in one of two orientations. This allows either the open-ended nut-engagement portion 31a or the closed-ring nut-engagement portion 31 b to be towards the exit of the mouth.

Figure 8 shows an alternative embodiment of the insert 30, with four nut-engagement portions. In this example all nut-engagement portions are of the open-ended type. There is a lip 34 on every external edge 33 of the insert 30. This allows the insert 30 to be slid into the mouth 21 of the wrench 1 in any of four orientations. To accommodate all orientations both the mouth 21 and insert 30 are square shaped. This delivers functionality for any one of the four open- ended nut-engagement portions.

Figures 9 and 10 show perspective views of the head 20. In this example there is even a recess along a throat 24 of the mouth 21 , as this enables the mouth 21 to receive an insert according to the embodiment shown in Figure 8 in any of the four orientations. Figure 9 shows a lock guide hole 41 through which the lock pin 40 can pass to ultimately engage the lock receiver 35 in the insert. In this example, the volume ratio of the mouth to the head (which includes the mouth) is between 0.15:1 and 0.4:1

It is envisaged that a wrench 1 could be provided as a kit with a plurality of inserts 30 of varying sizes of nut-engagement portions. This allows the wrench to be adapted to engage nuts of various sizes, as inserts can be slidably removed very easily, and a new insert slidably inserted and locked into place for subsequent use.

The wrench 1 of Figure 1 can be easily used in the usual manner to operate upon nuts to either tighten or undo said nuts. If a different sized insert is required, the insert can be unlocked by pressing lock 40, which is spring loaded on a latch, to release the lock from the lock receiver 35. The insert can then be easily slid out of the mouth 21 and a new insert of the appropriate size slid back into the mouth before locking it by again pushing lock 40 which, by virtue of a spring loaded latch mechanism, will engage the lock receiver 35 and hold the insert in place. The new insert can then be used to operate upon a nut.

Claims

CLAIMS:

1. A wrench comprising:

a handle; a head attached to the handle; a mouth within the head; and an insert within the mouth;

wherein the insert is slidably removable from the mouth and the insert comprises:

an open-ended and/or closed-ring nut-engagement portion.

2. The wrench as claimed in claim 1 , wherein the position of the mouth relative to the head is permanently fixed.

3. The wrench as claimed in any preceding claim, wherein the insert has an external edge which is substantially flush with an edge of the head.

4. The wrench as claimed in any preceding claim, wherein the insert has a thickness substantially the same as the thickness of the head around the mouth.

5. The wrench as claimed in any preceding claim, where in the insert comprises at least two nut-engagement portions.

6. The wrench as claimed in claim 5, wherein one of the at least two nut- engagement portions is open-ended.

7. The wrench as claimed in any of claims 5 or 6, wherein one of the at least two nut-engagement portions is closed-ring.

8. The wrench as claimed in any of claims 5 to 7 wherein the insert is rearrangeable to adopt at least one alternative orientation within the mouth.

9. The wrench as claimed in any preceding claim comprising a lock mechanism for releasably locking the insert within the mouth.

10. The wrench as claimed in any preceding claim, wherein the insert is a single solid piece.

11. The wrench as claimed in any preceding claim wherein the handle is removably attached to the head.

12. The wrench as claimed in claim 11 wherein the head is rearrangable to adopt at least one alternative orientation relative to the handle.

13. The wrench as claimed in any preceding claim, wherein the shape of the perimeter of the insert is substantially different form the shape of the nut-engagement portion.

14. The wrench as claimed in any preceding claim wherein the insert comprises a socket receiver for receiving sockets.

15. A wrench head for a wrench, the head comprising:

a mouth arranged to slidably receive an insert having an open-ended and/or closed-ring nut-engagement portion.

16. The wrench head as claimed in claim 15, whereby a volume ratio of the mouth to the head (which includes the mouth) is between 0.15:1 and 0.4:1.

17. An insert as described in any preceding claim, which insert is slidably insertable and slidably removable from a mouth of a head of a wrench, the insert comprising:

an open-ended and/or closed-ring nut-engagement portion.

18. The insert as claimed in claim 17, wherein a visible front face of the insert when in use within the mouth has a solid potion and an empty nut-engagement potion(s), and a ratio of surface areas of the solid portion to the empty nut-engagement portion(s) is between 1 :3.5 and 46:1.

19. The insert as claimed in any of claims 17 to 18 wherein the ratio of a diameter of the nut-engagement portion to a width of an outer portion of the insert is between 1 :4.5 and 3:1.

20. A kit of inserts comprising a plurality of inserts as described in any preceding claim.

21. A wrench kit comprising: a handle; a head as described in any of claims 1 to 16, either attached or removably attachable to the handle; and a plurality of inserts as described in any preceding claim.

22. A method of operating upon a nut, comprising the steps of:

a) slidably inserting an insert, as described in any preceding claim, into the mouth of the head of the wrench, as described in any of claims 1 to 16; b) engaging the nut with a nut-engagement portion of the insert; and c) turning the nut.

23. A wrench, wrench head, insert, kit of inserts, wrench kit, or method of operating upon a nut, as substantially hereinbefore described with reference to the diagrammatic drawings.