In the context of this specification, a'threaded fastener'is any article comprising a thread of any type that is used in co-operation with another thread to connect two or more articles (one of which may be the article itself) together. Typical examples of threaded fasteners are nuts, bolts and screws. Although threaded fasteners are universally employed, their inherent characteristic that they are operated by rotary movement can cause difficulties in confined spaces. This problem is particularly acute, for example, when connecting taps in sinks or baths to their respective water supply pipes, where access to the nut used to connect the tap to the pipe is restricted by the small amount of space generally available to work in.

In the case of a tap connection, it is not usually possible to use hand-tightening alone to complete the connection, as the restricted space does not allow for a proper grip to be obtained and therefore the use of a tool is required. Although it is often possible to use a general purpose wrench, the space constraints mean that this is not always the case and the use of a purpose-specific wrench is required. A known purpose-specific wrench adapted for such a use is shown in Figures 15 and 16.

The purpose-specific wrench 120 shown in Figure 15 comprises a shaft 129, with a handle 128. The handle 128 is attached by way of a hinge 127 to one end of the shaft 129 such that it can be moved through a range of angles relative to the shaft 129.

The other end of the shaft 129 comprises a head 132, provided with a lateral extension 126 and a fixed gripping portion 121. The lateral extension 126 comprises a bore 133 which accommodates a pivot pin 125 so that the pivot pin 125 is set parallel to the shaft 129. The fixed gripping portion 121 is axially offset from the shaft 129, diametrically opposite the bore 133 and axially distal the handle 128. An elbow-shaped moveable gripping arm 122 is journalled to the pivot pin 125 via a hinge 124, which is arranged perpendicular to the axis of the pivot pin 125. This dual-axis connection between the gripping arm 122 and the lateral extension 126 enables them to be manipulated between a nut release position, as shown in Figure 15 and a nut gripping position, as shown in Figure 16, by use of the shaft 129 and handle 128.

Whilst the wrench 120 is in the nut gripping position, the nut 130 may be rotated upon the pipe using the handle 128. This is facilitated by cooperating teeth 123,136, respectively provided on the gripping arm 122 and fixed gripping portion 121, which together serve to grip the nut 130. Once this operation has been completed, the engagement between the nut 130 and wrench 120 is released by downward movement of the shaft 129, so as to bring the tool 120 into the nut release position.

Although this purpose-specific wrench does overcome many of the problems associated with confined spaces, it is a complex tool and relatively expensive.

Furthermore, neither this wrench nor a general purpose wrench provides much, if any, feedback to the user as to the amount of force being applied, and it is therefore relatively easy to over-tighten a nut and subsequently damage a thread.

In the alternative, it is possible to purchase plastics connectors that can be hand- tightened, but these are generally regarded by persons working in the field as unsuitable for connection to metal threads for two reasons. The first is that a plastics screw thread is too easy to strip when connecting to a metal thread; the second is that the plastics can degrade over time if used with heated liquids, such as commonly conveyed in metal pipes.

In view of the foregoing, the present invention aims to provide a hand operable tool that can be used in confined spaces and that allows the user to feel how tight the connection between the threaded fastener and the thread to which it is fitted is, thereby reducing the likelihood of thread damage.

Accordingly, the invention provides a tool for rotating a threaded fastener on a screw thread, the said tool comprising: at least two component parts which can be separably connected together using connection means in order to assemble the tool; and at least one bearing surface on each component part for acting upon the threaded fastener to rotate it relative to the screw thread; wherein the tool can be assembled around the threaded fastener using a snap-fit action between the said connection means, so as to bring the said bearing surfaces into contact with the threaded fastener; and wherein the tool can be disassembled into the component parts by sliding one axially relative to the other, so as to allow their removal from the threaded fastener.

Such an arrangement enables the tool to be assembled when needed, around nuts, bolts or similar, and removed when no longer in use. Furthermore, it provides a tool that is compact enough to be used within confined spaces, such as those found behind sinks. Still further, it provides a hand-operable tool, which allows the user to determine, through direct feedback, the amount of force being exerted on the fastener, thus making it less likely that the fastener will be over-tightened.

The tool may comprise gripping portions with which the user can grip the tool to facilitate operation.

The said connection means may comprise a wedge and co-operatively shaped channel. In such a case, the wedge may comprise an arcuate camming surface and a wall of the said channel being defined by a resilient tongue which is adapted to travel over the said camming surface during assembly of the tool and to resiliently engage the said component part upon which it is not formed in order to secure engagement between that component part and the component part upon which it is formed after assembly of the said tool.

The tool may be configured such that operation of the tool causes the said bearing surfaces on respective component parts to be urged into tighter engagement with the said threaded fastener.

The tool may further comprise a flange located in an axial region of at least one of the said bearing surfaces for constraining the relative axial positions of a said component part and the said threaded fastener during use.

The said bearing surfaces may be stepped in order to fit a plurality of different sized threaded fasteners.

Preferably, there are two said component parts and these are substantially identical.

The tool may be such that each said component part comprises the said bearing surfaces arranged such that adjacent bearing surfaces are at an angle of substantially 120° with respect to each other, the arrangement being such that bearing surfaces define a hexagonal socket when the tool is assembled for use.

The tool may comprise a pair of the said connecting means with a part of each member of the said pair being located on each of the said component parts.

The said tool may comprise two said component parts which are discrete.

The said tool may comprise two said component parts which are connected together by intermediate connecting means.

Further features and advantages of the invention will become apparent from the claims, to which the reader is referred, and from a consideration of the following description of preferred embodiments of the invention and variations thereof, made with reference to the accompanying drawings in which like reference symbols indicate the same or similar components, and wherein: Figure 1 is an isometric view, from the top, of a tool according to the invention; Figure 2 is an end elevation of the tool of Figure 1; Figure 3 is a plan view, from below, of the tool of Figures 1 and 2; Figure 4 is a side elevation of the tool of Figures 1 to 3; Figure 5 is an isometric view, from below, of the tool of Figures 1 to 4; Figure 6 is a plan view, from the top, of the tool of Figures 1 to 5; Figure 7 is an isometric view, from above, of a component part of the tool of Figures 1 to 6; Figure 8 is an end view of the component part of the tool of Figure 7; Figure 9 is a plan view, from below, of the component part of the tool of Figures 7 and 8 ; Figure 10 is a plan view, from above, of the component part of the tool shown in Figures 7 to 9; Figure 11 is an isometric view, from below, of the component part of the tool of Figures 7 to 10; Figure 12 is an isometric view of the two component parts of the tool of Figures 1 to 11 seen from below immediately prior to coupling; Figure 13 shows the tool of Figures 1 to 12 in use rotating a nut along a screw thread; Figure 14 shows the component parts of the tool of Figures 1 to 13 being separated from a nut; Figure 15 is a view of a known purpose specific wrench; Figure 16 is a plan view illustrating the interaction of the wrench of Figure 15 with a nut; Figure 17 is an isometric view of the two component parts of the tool where the bearing surfaces are axially stepped; Figure 18 is a plan view illustrating an alternative embodiment of the tool; Figure 19 is an isometric view of the embodiment in Figure 18; Figure 20 is a plan view illustrating a further alternative embodiment of the tool; and Figure 21 is an isometric view of the embodiment in Figure 20.

Figures 1 to 14 illustrate a preferred embodiment of a tool 1 according to the invention. The tool 1 is formed from two identical component parts 3,5. The component parts 3,5 can be releasably fitted together into an operating condition such as shown in Figure 1. The tool 1 is generally rhomboidal in plan view when so assembled into the operating condition.

Each of the component parts 3,5 is in the form of a single piece comprising a body portion 8 having three respective peripheral bearing surfaces 7. Adjacent bearing surfaces 7 are arranged at 120° with respect to each other, so that they together define a hexagonal socket when the tool 1 is in the operating condition. This socket is used to bear upon a bolt head, a nut or the like in order to drive rotation of the bolt or nut relative to another threaded member in a conventional manner.

Each component part 3,5 is further provided with a respective wedge member 17, which is generally circumferentially directed relative to the socket in the assembled tool 1. Each wedge member 17 projects from the main body 8 of its respective component part 3,5. The thickness of each wedge, as measured in the radial direction relative to the socket of the assembled tool 1, decreases from a proximal region to a distal region. A radially inner surface 21 of each wedge is essentially planar and therefore generally tangential to the socket of the assembled tool 1. A radially outer surface 23 of each wedge member 17 is planar for most of its length extending from the distal end of the wedge member 17, but comprises a convex arcuate camming surface 19 in a proximal region of the wedge member 17.

Diametrically opposite its respective wedge member 17, each component part 3, 5 comprises a correspondingly configured channel 22. The profile of the channel 22 closely matches that of the wedge member 17, when viewed in plan. The channel 22 and wedge member 17 are of such similar dimensions that, when the tool 1 is assembled into the operating condition such as shown in Figures 1 and 3, there is little noticeable friction between the two component parts 3,5 when they are moved relative to each other in a direction which is axial with reference to the socket of the assembled tool 1.

The two major side surfaces of each component part 3,5, which serve to define the primary sides of the rhomboid when the tool 1 is assembled into the operating condition, are each provided with a series of clustered, parallel ribs 10 which extend in a direction parallel to the axis of the socket and which together define two finger grips 9 on each component part 3,5. Each grip 9 is positioned approximately midway along the respective side in which it is situated, so that the grips 9 are arranged in diametrically opposing pairs when the tool 1 is assembled into the operating condition.

Each component part 3,5 is further provided with an indent 11 situated on its radially outer surface, relative to the socket of the assembled tool 1, at a position which corresponds with an obtuse rhomboid corner of the assembled tool 1. Each indent 11 is arcuate in plan and terminated at one axial end by a finger stop 15 represented by a flange.

The bearing surfaces 7 of each component part 3,5 are terminated, at the same axial end as the indents, by a common radially inwardly directed flange 13, which has a part-circular radially inward periphery. The flange 13 is so configured that, upon assembly of the tool into the operating condition, it forms a circular aperture 14.

Each body portion 8 is penetrated by a blind bore 27, which is somewhat triangular when viewed in plan. This bore is essentially to reduce weight and save materials.

The tool 1 is assembled into the operational condition shown in Figure 1 by snap-fitting two component parts 3,5 together. Because each component part 3,5 is essentially identical, the component parts 3,5 do not have to be a pre-defined matched pair. They could simply be two such component parts 3, 5 conveniently selected from a group.

To fit the two component parts 3,5 together, they are presented to each other in the manner shown in Figure 12. As will be apparent from this figure, the two component parts 3,5 are orientated with their respective bottom surfaces 26 generally coplanar and with the distal end of each wedge 17 inserted into the mouth of the channel 22 of the other component. It will be noted that the planar, inner surface 21 of each wedge is aligned with and partly abutting the correspondingly configured surface of the channel 22 into which it is inserted. At this stage, each outer tongue 23 addresses the lead edge of the arcuate camming surface 19 of the wedge member 17 of the other component parts 3,5.

The two component parts 3,5 are brought into full engagement by manually squeezing them together using the indents 11. As this squeezing operation applies compressive force, the outer tongues 23 move over the respectively adjacent arcuate camming surfaces 19 of the wedge members 17 of the opposite component parts 3,5 and are urged to flex radially outwardly. As the compressive force continues, the tips of the outer tongues 23 proceed over portions of the camming surfaces 19 which return radially inwardly, thereby allowing the outer tongues 23 to hook around the camming surfaces 19 under the power of their inherent resilience and lock the two components together, as the wedge members 17 become fully received within the respective channels 22 and the facing surfaces of the bodies 8 of the two component parts 3,5 are brought into abutment. Due to the respective shapes of the outer tongues 23 and the arcuate camming surfaces 19, as well as the directional guidance provided by the inner surfaces 21 of the wedges and the respectively configured surfaces of the channels 22, an initial application of a squeezing force by the user results in a relatively rapid, accelerating connection between the two component parts 3,5 in the manner of a snap- fit.

In practice, the two component parts 3,5 are snapped together in the above- described manner around a nut, bolt or other threaded fastener, which is then presented to the other threaded articles thereby typically resulting in an arrangement such as shown in Figure 13. In Figure 13, the tool 1 has been snapped together about a nut 29 of a pipe fitting 32 which is to be connected to a tap supply 31 having a threaded radially outer surface. It will be appreciated from this figure that the flanges 13 locate with their circular inner aperture about the fitting 32 and serve to support the axial position of the tool 1 relative to the nut 29. This is advantageous, because the two component parts 3,5 of the tool 1 are configured such that they may slide axially relative to one another whilst in the assembled, operational condition shown in Figure 13. The flanges 13, by abutting against the nut 29, essentially serve to secure the axial positions of the two component parts 3,5 relative to each other whilst a turning force is applied in order to rotate the nut 29 upon the tap supply 31.

After the nut 29 has been screwed to its appropriate position, the user simply allows or encourages one of the two component parts 3, 5 to move axially downward, as shown in Figure 14. The component parts 3,5 are then separated from each other and may be removed.

During operation of the tool 1 upon the nut 29, the user grips the tool 1 using the grips 9, in order to apply the necessary rotational force. It will be noted that the relative positioning of the grips 9 and the internal formations of the components defining the bearing surfaces 7, along with the configuration of the wedge members 17, serves to increase the gripping force applied by the bearing surfaces 7 to the nut 29, as the tool 1 is rotated.

The simple snap-fit assembly of the tool 1 about the nut 29 means that it is easy for a user to apply the tool 1 to the nut 29 in a confined space with little or no visibility.

Furthermore, the tool 1 enables the user to obtain direct feedback regarding the installation operation, thereby reducing or completely removing the risk of over- tightening the nut 29 and stripping a thread. The tool 1 can be used with a metal nut or other component, thereby overcoming the various above-described disadvantages associated with the use of plastics components. A further advantage of this tool is that the nut is encapsulated, which means that the tool can be used to present it to the pipe, which is particularly beneficial where space is particularly constrained or where it is difficult or impossible for the user actually to see the pipe. All of these advantages do, of course, apply equally in respect of other types of threaded fasteners fitted to other types of threaded articles.

The tool 1 is, in this embodiment, made from polypropylene, which is easy to mould, gives a degree of flexibility and resilience suitable for allowing the snap-fit assembly of the fitting, yet also provides sufficient strength and durability to enable repeated re-use and to enable the tool to apply a relatively high torque during installation procedures.

Although the above-described embodiment normally makes use of a snap-fit to join the two components, it is possible for the two component parts 3,5 to be joined together by sliding axially, in an operation which is essentially the reverse of the described separation operation. This being the case, the components could be formed from a much less resilient material than polypropylene, such as brass. Whilst such an embodiment lacks some of the simplicity of assembly of the above-described embodiment, the resulting tool would be significantly more durable.

Although this embodiment has been described with particular reference to the installation of a nut of a fitting upon a threaded pipe, it has a very wide range of possible uses and can just as easily be used with bolts as well as nuts. Indeed, embodiments of the invention are suitable for use in any situation where it is required to rotate a threaded fastener upon some other threaded object.

The above-described embodiment is merely illustrative and numerous modifications and variations are possible within the context of the invention. The connection means defined by the wedge members 17 and channels 22, could be replaced by numerous variations which enable the two component parts to interlock with each other. Furthermore, although six bearing surfaces 7 are provided on the embodiment described above, more or fewer surfaces could be included. Indeed, it is possible to construct a tool in accordance with the invention which includes just two bearing surfaces. These would typically be generally parallel to each other in the assembled tool. In such an arrangement, it is possible for the tool to be adjustable for use with threaded fasteners of different sizes. All that is required is for a mechanism which allows the separation of the bearing surfaces to be set at different values to be provided.

One example of this would be to provide a ratchet mechanism on the elements of the components which are used for joining them together. The ratchet mechanism enables the two components to be urged together until a suitable bearing surface separation is reached and yet they can still be slid apart axially in the same manner as the above- described embodiment, when required.

In a further variation, the bearing surfaces may be axially stepped, as seen in Fig. 17, so that the socket of the assembled tool has two or more axial regions of different diameters. Such a tool is then configured for use with a corresponding number of different threaded fastener diameters.

Although the two component parts 3,5 are shown as discrete elements, it is within the scope of the invention for them to be connected together in various ways.

For example, they could be linked by a cord or chain or even hinged together.

An example of an alternative snap-fit connection is shown in Figures 18 and 19, where the wedge member is formed with a bulbous shape, and the channel is correspondingly configured. Construction of the tool is accomplished by applying a closing force to the two component parts, resulting in the bulbous shaped wedge member displacing the narrower lips of the corresponding channel such that the wedge member is able to snap-fit into the channel.

Another example is shown in Figures 20 and 21, where the wedge member is shaped substantially as in Figures 18 and 19, but one half of the wedge member is squared off. For construction of the tool in this embodiment, again a closing force is applied, but as only one side of the wedge member is protruding, only one side of the channel has a lip that needs to be displaced for the two component parts to snap-fit together.

The embodiments shown in Figures 18 to 21 may also be assembled by axial sliding as with the above described embodiment.