TECHNICAL FIELD

The invention relates to a rotation indicator device. The invention particularly, though not necessarily, relates to a rotation indicator device for mounting onto a fastener, e.g. a wheel nut, or other component, either having a multi-angular peripheral surface, or a circular peripheral surface.

BACKGROUND

Various types of rotation indicator devices are known and such devices are widely used on heavy goods vehicles as a safety device to indicate the occurrence of loosening of individual wheel nuts. Many examples of known devices are described in earlier patent specifications, e.g. GB2242720 discloses a rotation indicator device comprising a body having a bore formed with equispaced groves enabling the device to be releasably mountable onto a wheel nut in a manner that inhibits a relative rotation of the device and the wheel nut. Thus, the device only rotates upon rotation of the wheel nut, such as when the wheel nut loosens, thereby indicating the rotation. The bore is sized for a given size of wheel nut, and devices of this type are typically made of a plastics material. It is an object of embodiments of the invention to at least mitigate one or more problems of known devices.

SUMMARY OF THE INVENTION

According to the invention, there is provided a rotation indicator device for mounting onto a fastener, such as a wheel nut, the device comprising a resilient wire forming a coil, e.g. only a single coil, for releasably mounting the device onto a fastener, the wire having first and second end portions, which converge or extend tangentially from the coil toward one another. In use, pulling apart of the first and second end portions may loosen the coil, for example to enable its location over, or removal from, the fastener. The coil may otherwise grip the fastener when located thereover, for example to mount the device onto the fastener such that movement of the device relative to the fastener is inhibited, at least when mounted onto a fastener. The first and second end portions may terminate adjacent one another, for example to form a pointer on a side of the device for indicating the position or orientation of the device relative to a reference.

In developing the invention, it was identified that plastics material is not always appropriate for some environments. This invention provides a cost effective alternative to the indicator device of GB2242720, which is adapted for use in more aggressive environments.

In addition, the orientation of the rotation indicator device according to this invention may be placed over the fastener in any desired orientation. The orientation of installation of the indicator device of GB2242720 requires alignment between a feature of the fastener and the grooves in the bore of the indicator device.

The coil may describe an inner diameter. The end portions are straight and/or linear. The end portions may describe, e.g. together describe, an angle therebetween. The end portions may describe a first angle when the device is in a relaxed state. The end portions may describe a second angle when the coil is mounted over a fastener. The second angle may be smaller than the first angle when the coil is mounted over a fastener having a larger diameter than the inner diameter described by the coil.

The first angle may be less than 180 degrees. Preferably, the first angle is 120 degrees or less. More preferably, the first angle is 90 degrees or less. The first angle may be between 30 and 90 degrees, such as between 30 and 60 degrees.

The second angle may also be less than 120 degrees. Preferably, the first angle is less than 90 degrees. More preferably, the second angle is less than 60 degrees. The second angle may be between 15 and 60 degrees, such as between 15 and 45 degrees.

The pointer may be substantially triangular in shape. In some examples, the end portions need not be straight and/or linear, they may be curved. The end portions may have opposed surfaces that are concave or convex.

The end portions may overlap, for example when the device is in a relaxed state. The end portions may overlap, for example when the device is mounted to a fastener and/or when the coil grips the fastener.

The wire may have any suitable cross-section, such as round, elliptical or polygonal. Preferably, the wire has a square or rectangular cross-section. The end of at least one or each end portion may be chamfered or bevelled.

Another aspect of the invention provides a kit of parts for assembly into a rotation indication system. The kit may comprise one or more fasteners, such as wheel nut(s), and a rotation indicator device as described above.

Another aspect of the invention provides a wheel assembly comprising a fastener with a rotation indicator device mounted thereon.

Yet another aspect of the invention provides a vehicle comprising a wheel assembly as described above.

Another aspect of the invention provides a method for detecting rotation of a fastener, such as a wheel nut. The method may, but need not, involve the use of the rotation indicator device described above. The method may comprise pulling apart first and second end portions of a resilient, coiled wire, for example to loosen the coil. The method may comprise mounting the loosened coil onto a fastener. The method may comprise releasing the first and second end portions, for example such that the coil grips the fastener such that movement of the device relative to the fastener is inhibited.

The method may comprise detecting rotation of the fastener, for example when the device rotates relative to a reference.

The method may comprise pulling apart the end portions of the resilient, coiled wire to loosen the coil, e.g. when it is mounted to the fastener and/or when the coil grips the fastener. The method may comprise removing the device from the fastener.

The first and second end portions may converge toward one another, for example to form a pointer on a side of the device. The end portions or point may be for indicating the position or orientation of the device relative to a reference.

The end portions may describe a first angle, for example before they are pulled apart. The end portions may describe a second angle, for example when the device is mounted to or over a fastener and/or after the end portions are released. The second angle may be smaller than the first angle. The end portions may overlap, for example before and/or after they are pulled apart.

The first angle may be between 30 and 90 degrees and/or the second angle may be between 15 and 60 degrees. Other angles are also possible, as explained above in relation to the rotation indicator device.

For the avoidance of doubt, any of the features described herein apply equally to any aspect of the invention. For example, the rotation indicator device may comprise any one or more features of the method relevant thereto and/or the method may comprise any one or more features or steps relevant to one or more features of the rotation indicator device.

Another aspect of the invention provides a computer program element comprising and/or describing and/or defining a three-dimensional design for use with a simulation means or a three-dimensional additive or subtractive manufacturing means or device, e.g. a three-dimensional printer or CNC machine, the three-dimensional design comprising an embodiment of the rotation indicator device described above.

A yet further aspect of the invention provides the computer program element embodied on a computer readable medium.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible.

For the avoidance of doubt, the terms “may”, “and/or”, “e.g.”, “for example” and any similar term as used herein should be interpreted as non-limiting such that any feature so-described need not be present. Indeed, any combination of optional features is expressly envisaged without departing from the scope of the invention, whether or not these are expressly claimed. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying figures, in which: Figure 1 is a perspective view of a rotation indicator device according to an embodiment of the invention, shown in a relaxed state;

Figure 2 is a plan view of the rotation indicator device of Figure 1; Figure 3 is a side view of the rotation indicator device of Figures 1 and 2;

Figure 4 is a perspective view of the rotation indicator device of Figures 1 to 3, shown in a flexed state; and Figure 5 is a plan view of the rotation indicator device of Figures 1 to 4 mounted on a fastener.

DETAILED DESCRIPTION

As illustrated in Figures 1-5, there is provided a rotation indicator device 1 for mounting onto a fastener F, such as a wheel nut. While the device 1 has particular application as locking device to inhibit loosening of wheel nuts, the device 1 may also be used to inhibit loosening of other screw action fasteners, including polygonal fasteners and other components having a multi-angular peripheral surface. The device 1 includes a resilient wire 2 formed into a coil 3 with end portions 4, 5 extending tangentially from the coil 3, and which converge toward one another.

The wire 2 has a substantially square cross-section in this embodiment, but other cross-sectional shapes are also envisaged without departing from the scope of the invention. The wire 2 is formed into a coil 3 having at most a small gap between its turns, as illustrated more clearly in Figure 3, and having straight, linear end portions 4, 5. The end 40, 50 of each end portion 4, 5 is bevelled or chamfered, to provide an end surface that forms an oblique angle. The specific shape and configuration of the coil 3 and the end portions 4, 5 may vary from this, specific example. The coil 3 of the specific example has one complete turn, as well as a portion of an incomplete turn. In embodiments of the invention, the coil 3 may have any number of complete turns.

When the device 1 is in a relaxed state, as illustrated in Figures 1 to 3, the coil 3 describes an inner diameter Di and the end portions 4, 5 describe a first angle 0^. In this example, the first angle 01 is approximately 45°, but it is envisaged that any angle between 30 and 90 degrees functions very well. Other angles are also possible without departing from the scope of the invention.

In this, relaxed state the end portions 4, 5 overlap, such that they extend beyond one another and diverge thereafter toward their ends 40, 50. Whilst other configurations are envisaged, this overlap facilitates a user’s ability to install the device 1 onto the fastener F. In certain embodiments, in the relaxed state, the end portions 4, 5 terminate adjacent one another.

In order to install the indicator device 1 onto a fastener F, the end portions 4, 5 must first be pulled apart, as illustrated by the arrows P. This can be achieved using an appropriate tool (not shown) which, as a result of the overlap between the end portions 4, 5, can be in the form of a clamping tool (not shown). Other tools can also be used.

This pulling force P causes the coil 3 to loosen, or unwind slightly, thereby increasing the inner diameter to a value larger than Di. The loosened coil 3 can then be placed over the fastener F, whilst applying the pulling force P to the end portions 4, 5. Once the coil 3 is in the desired position, surrounding the fastener F, the end portions 4, 5 can be released, which causes the coil 3 to contract toward its relaxed state. However, the fastener F is larger than the inner diameter Di of the coil 3 in its relaxed state. As such, the presence of the fastener F precludes complete contraction. Instead, the coil 3 is only able to contract to the point at which it grips the fastener F, by virtue of the resiliency of the coil 3. The inner diameter D ₂ in this configuration corresponds to the largest, effective diameter D ₂ of the hexagonal fastener F across its vertices. As a result of the contracting force applied to the fastener F by the coil 3, movement of the device 1 relative to the fastener F is inhibited.

In this, installed state, the end portions 4, 5 converge toward and terminate adjacent one another to form a triangular shaped pointer 6 on a side of the device 1. This pointer 6 is useful for indicating the orientation of the device 1 relative to a reference. In this example, the end portions 4, 5 overlap only slightly, to the point at which each bevelled end 40, 50 is aligned with the adjacent edge of the opposite end portion 5, 4. This provides a pointer 6, which provides a more distinguishable, triangular pointer 6 which is aesthetically superior to one without the bevels. In certain embodiments, the end portions 4, 5 converge toward and terminate adjacent one another without any overlap.

When the device 1 is in the installed state, as illustrated best in Figure 5, the end portions 4, 5 describe a second angle 0 ₂ , which is smaller than the first angle 0^. In this example, the second angle 0 ₂ is approximately 30°, but it is envisaged that an angle between 15 and 60 degrees functions very well. Other angles are also possible without departing from the scope of the invention.

In use and when the device 1 is mounted to the wheel nut F of a vehicle wheel assembly, undesirable rotation of the wheel nut F can be readily appreciated, since the pointer 6 will rotate relative to a reference (not shown). That reference may be in any form, for example a mark on the wheel rim (not shown) or other part of the wheel assembly. Alternatively, the reference may be provided by a feature of the wheel assembly, e.g. wheel rim (not shown), itself such as a hole, rivet, flange, rib or other feature. The reference may be a pointer of an adjacent at least similar device, e.g. mounted on an adjacent faster.

Removing the rotation indicator device 1 can be achieved by the reverse of the aforementioned process. More specifically, the end portions 4, 5 can be pulled apart to loosen the coil 3, thereby enabling the device 1 to be removed from the fastener F.

Embodiments of the invention may be made of spring steel wire. Spring steel is generally low-alloy manganese, medium-carbon steel or high-carbon steel with a high yield strength. Embodiments of the invention may be made stainless steel wire, for example 301 stainless steel wire, a grade of steel also known as X10CrNi18-8. The aforementioned materials provide the necessary resiliency to deform the device 1, allowing it to return to its original shape and the gripping force on a fastener F. Flowever, any material that exhibits the necessary resiliency would be suitable.

It will be appreciated by those skilled in the art that several variations to the aforementioned embodiments are envisaged without departing from the scope of the invention. It will also be appreciated by those skilled in the art that any number of combinations of the aforementioned features and/or those shown in the appended drawings provide clear advantages over the prior art and are therefore within the scope of the invention described herein.