Field of the Invention

The present invention relates to a nut for use with tools which are used to apply torque to rotary fasteners such as nuts. In particular, the invention relates to a safety nut which secures such a tool to the fastener and prevents such a tool from falling during use.

Background of the Invention

Tools such as spanners, wrenches and hydraulic torque wrenches are used to apply torque to turn objects, usually rotary fasteners such as nuts. When using manual tools such as spanners and wrenches, the tool is placed around the fastener and manual force is applied to turn the fastener. Hydraulic torque wrenches are power tools used to exert torque on fasteners to either tighten or loosen the fastener. A hydraulic torque wrench is placed around a fastener and is then held in position as the torque is applied.

There exist risks of accident and/or injury when using such tools. For example, there exists a risk of the tool falling away from the nut during use, particularly if the fastener is oriented such that gravity would assist such a fall. Also, the fastener often 'gives' suddenly, particularly when it is being loosened, and if the tool is not held securely in place by the operator there exists both a risk of the tool falling with potential to cause injury and/ or damage to the tool, as well as a risk of injury to the operator, including the accidental trapping of fingers between the tool and other parts of the equipment being worked on. This is particularly an issue when using hydraulic torque wrenches, which apply very large forces to fasteners.

It would be desirable to provide an apparatus which helps to secure a tool in position during use, and that could allow hands free operation of hydraulic torque wrenches.

Summary of the Invention

According to a first aspect of the invention there is provided an apparatus for for securing a tool to a fastener on an externally threaded member, the fastener having a diameter, the apparatus comprising:

a nut portion, the nut portion having a bore therethrough, the bore being provided with an internal thread corresponding to the thread of the externally threaded member;

a securing element, the securing element having an opening therethrough and being connectable to the nut portion, wherein the securing element has a maximum diameter that is greater than the diameter of the fastener; and

means for fastening the securing element to the nut portion.

Preferably the diameter of the securing element is at least 10mm larger than the diameter of the fastener. The diameter of the securing element must be sufficiently larger than the diameter of the fasteners to prevent the tool from falling from the fastener during use.

Preferably the securing element is provided with a plurality of projections which extend outwards radially. The maximum diameter of the securing element is considered to be the diameter of a circle circumscribing the tangent edges of the projections. Preferably the projections are spaced equally around the securing element.

Preferably the securing element is rotatable about the nut portion. When the securing element is rotatable about the nut portion the positions of the projections can be altered whilst maintaining a tight connection of the nut portion to the bolt. This is an advantage when access to the fastener is difficult.

Preferably the securing element is a plate.

The externally threaded member may be a bolt or a threaded bar.

The apparatus is preferably provided in parts such that nut portions with different bore diameters and different thread counts or thread pitches can be used depending on the particular bolt assembly.

The apparatus of the invention may be used with any tool which fits over a fastener. For example, the tool may be selected from the group comprising ring spanners, open ended spanners, wrenches, and hydraulic torque wrenches. Preferably the nut portion has a front side and a rear side and the securing element is secured to the rear side of the nut portion.

Preferably the means for fastening the securing element to the nut comprises a split ring such as a circlip. Preferably the split ring locates in a groove located on the rear side of the nut portion.

Preferably the front side of the nut portion is provided with gripping elements. Gripping elements help a user to tighten the apparatus on the bolt.

Preferably the securing element comprises at least three projections.

According to a second aspect of the invention, there is provided a method for tightening or loosening a fastener on a bolt the method comprising the steps of;

a) applying a tool to the fastener;

b) attaching an apparatus for securing a tool according to any of Claims 1 to 5 to the externally threaded member by threading the apparatus onto the externally threaded member;

c) using the tool to tighten or loosen the fastener; and

d) removing the apparatus for securing the tool from the externally threaded member by unthreading the apparatus therefrom.

The position of the securing element relative to the nut may be adjusted by rotating the securing element about the nut.

Preferably, the apparatus includes a flexible attachment element extending from one of the nut portion and the securing element. The securing element may include a hole and the flexible element is attached to the hole. The hole may be comprised in a tab extending from the securing element. The flexible element may be provided with attachment means for attaching the flexible element to another object. For example, the flexible element may comprise a lanyard, typically a flexible wire, with attachment means at each end. The lanyard may be attached to the securing element by a clip such as a key ring and the other end of the lanyard may be provided with a quick release clip.

It is advantageous hat a quick release clip is provided at the free end of the flexible element so that it may be released and reattached to an object as the operator of the tool desires. However, the flexible element may be fastened to the securing element and or a clip at the free end of the flexible element in a fixed manner. For example, the flexible element may pass through a hole in the securing element to form a loop which cannot be opened easily. Similarly, the clip at the free end of the flexible element may be attached in a similar way.

According to a third aspect of the invention, there is provided a kit of parts for securing a tool to a fastener on an externally threaded member, the kit comprising:

a plurality of nut portions, each nut portion having a bore therethrough and being provided with an internal thread corresponding to a particular external thread;

at least one securing element, the or each securing element having an opening therethrough and being connectable to a nut portion, wherein the fastener has a diameter and the or each securing element has a maximum diameter that is greater than the diameter of the fastener; and

means for fastening the or each securing element to a nut.

Preferably, the or each securing element comprises a plurality of outwardly extending projections. The maximum diameter of the or each securing element is considered to be the diameter of a circle circumscribing the tangent edges of the projections. Preferably the projections are spaced equally around the securing element.

Preferably the or each securing element is a plate.

The apparatus of the invention helps secure a tool to a fastener and allows hands-free operation of power tools such as hydraulic torque wrenches, preventing accidents associated with the use of such tools.

Brief Description of the Drawings

In the drawings, which illustrate a preferred embodiment of the apparatus of the invention, and are by way of example:

Figure la is perspective view, from the front, of an embodiment of the apparatus of the invention;

Figure lb is a perspective view, from the rear side, of the embodiment of Figure la; Figure 2a is an exploded view of the apparatus of Figure la;

Figure 2b is an exploded view of the apparatus of Figure lb; Figure 3 is a plan view of a fastener;

Figure 4 is a plan view of the securing element portion of the apparatus of Figure la;

Figure 5 illustrates a hydraulic torque wrench located around a fastener prior to connection of the apparatus of Figure la;

Figure 6 illustrates a hydraulic torque wrench located around a fastener with the apparatus of Figure la attached to the bolt adjacent the wrench; and

Figure 7 is a schematic representation of an alternative embodiment of the apparatus of the invention.

Detailed Description of the Preferred Embodiments

Referring to Figures la, lb, 2a and 2b, the apparatus of the invention, shown generally at 1, comprises a nut portion 2, a securing element or plate 3 and a circlip or snap ring 4. The plate 3 is provided with three arms or projections 5 which each extend radially outwards and are spaced equally around the circumference of the plate 3. The nut portion 2 has a bore therethrough the diameter of which corresponds to the bolt to which it is to be attached and the bore is provided with an internal thread 6 which also corresponds to the thread count or pitch of the bolt to which the apparatus is to be attached (see Figures 3 and 4). The plate 3 has a bore therethrough which is shaped to locate over the rear side of the nut portion 2. After the plate 3 is located on the rear side of the nut portion, the circlip 4, which is a semi-flexible ring with open ends, is snapped into place inside a groove 7 on the rear side of the nut portion 2. The circlip 4 secures the plate 3 in place, but still allows the plate 3 to rotate around the nut portion.

A kit may be provided comprising several different nut portions, each corresponding to a different bolt diameter and/ or a different thread count or thread pitch. Each nut portion 2 would be connectable to a plate 3 using a circlip 4. The apparatus 1 is assembled with the plate 3 and circlip

4 attached to the appropriate nut portion 2 prior to use.

Referring now to Figures 3 and 4, the diameter Y of the plate 3 must be larger than the across corners diameter, X, of the fastener 10 to enable the plate to prevent a wrench from falling away from the fastener 10. As shown in Figure 4, the diameter Y of the plate 3 is considered to by the diameter of a circle circumscribing the tangent edges of the projections 5. Preferably the diameter Y of the plate 3 is at least 10mm larger than the cross corners diameter, X, of the fastener 10.

Different sizes of apparatus 1 may be used with different sized fasteners. As an example, the apparatus may be provided in three sizes as follows:

A first size may be for use with smaller fasteners 10, typically with an across corners diameter, X, of, for example, between approximately 31 and 70mm. The plate 3, for use with fasteners 10 of this size would typically have an diameter, Y, of approximately 80mm, meaning that the difference between the diameter Y of the plate 3 and the across corners diameter X of the fastener lies in the range 10mm to 49mm.

Larger fasteners 10, for example those with an across corners diameter, X, of between approximately 70 and 103mm, would require a plate 3 with a larger diameter Y, for example of around 123mm, meaning that the difference between the diameter Y of the plate 3 and the across corners diameter X of the fastener lies in the range 20mm to 59mm.

Even larger fasteners 10, for example those with an across corners diameter, X, of between approximately 114 and 125mm or larger, would require a plate 3 with a larger diameter Y, for example around 200mm, meaning that the difference between the diameter Y of the plate 3 and the across corners diameter X of the fastener lies in the range 75mm to 86mm. These are only examples of possible sizes of both fasteners 10 and plates 3, other sizes and combinations are possible within the scope of the invention.

Referring now to Figure 5, a hydraulic torque wrench 9 is shown set in position around a fastener 10 located on a bolt 11. The apparatus 1 is assembled such that bore diameter and the internal thread 6 of nut portion 2 matches the thread 12 and diameter of the bolt 11. The apparatus 1 is then threaded onto the bolt 11 and tightened by hand, such that the apparatus 1, and particularly the plate 3, is located immediately adjacent the hydraulic torque wrench 9. The nut portion 2 is preferably provided with gripping elements 8 which help a user to hand tighten the apparatus 1 around the bolt 11. Figure 6 illustrates the apparatus 1 in position adjacent the wrench 9. As shown in Figure 6, the projections 5 of the plate 3 extend outwardly beyond the diameter of the fastener 10 and interfere with the wrench 9, preventing the wrench 9 from falling off the fastener. This means that the user no longer needs to hold the wrench 9 in position during operation, since the wrench 9 is held in position with the apparatus 1. Since the plate 3 is rotatable about the nut portion 2 of the apparatus 1 it means that in tight spaces the particular location of the projections 5 can be adjusted so that the wrench 9 remains tightly secured to the bolt 11 by the apparatus 1. After the fastener 10 has been either tightened or loosened using the hydraulic torque wrench 9, the apparatus 1 is removed from the bolt 11 and then the wrench 9 can also be removed from the fastener 10.

Referring now to Figure 7, extending from the plate 3 is a connection element in the form of a tab 15. The tab 15 includes a hole 15a. A clip in the form of a keyring 16 is attached to the tab 15 through the hole 15a. A first loop 17a of a lanyard 17 is also attached to the keyring 16. The other end of the lanyard 17 also has a loop 17b. A clip 18 is attached to the loop 17b. In the illustrated embodiment the clip 18 is a quick release clip and includes two sprung elements 18a, 18b. The first spring element 18a provides for attachment of the clip 18 to the loop 17b, whilst the second spring element 18b provides for attachment of the clip 18 to another component, for example the torque wrench 9. The advantage of providing a lanyard within the apparatus 1 is that the apparatus may be tethered to another component, thereby reducing the risk of the apparatus becoming lost or falling from a height, which may have potentially dangerous consequences.