GB2615149A

GB2615149A - Adjustable luminaire

Info

Publication number: GB2615149A
Application number: GB2209917.0A
Authority: GB
Inventors: Healey Matt
Original assignee: John Cullen Lighting Ltd
Current assignee: John Cullen Lighting Ltd
Priority date: 2022-07-06
Filing date: 2022-07-06
Publication date: 2023-08-02
Anticipated expiration: 2042-07-06
Also published as: GB2615149B; GB202209917D0

Abstract

An adjustable luminaire comprising: a first part (10 fig. 1); a second part (20); an attachment structure (30) attaching the first part to the second part such that the second part is able to rotate about the first part. A washer 36 is located between one or more of: the attachment structure and the first part; and the attachment structure and the second part; wherein the washer is arranged to enable the attachment structure to move relative to the washer as the second part is rotated about the first part. The attachment structure may comprise a bolt or screw 32 interacting with a nut 34. The washer may be a low friction material such as nylon and there may be a further washer 38 which may be a compressible washer such as rubber or silicon rubber.

Description

Adjustable luminaire

Field of the disclosure

The present disclosure relates to an adjustable luminaire, to a method of adjusting the luminaire, to an adjustment structure for a luminaire, and to a kit of parts for an adjustable luminaire.

Backqround of the disclosure

To control the output of a luminaire, it is known to provide adjustable luminaires for which users are able to tilt or pan an optical element of the luminaire so as to adjust a lighting direction. However, conventional luminaires have a number of drawbacks, such as adjustment mechanisms that lack user-friendliness or robustness.

Summary of the disclosure

Aspects and embodiments of the present disclosure are set out in the appended claims. These and other aspects and embodiments of the disclosure are also described herein.

According to a first aspect of the present disclosure, there is provided an adjustable luminaire, the luminaire comprising: a first part; a second part; an attachment structure arranged to attach the first part to the second part such that the second part is able to rotate about the first part; and a (optionally low friction) washer located between one or more of: the attachment structure and the first part; and the attachment structure and the second part; wherein the washer is arranged so that the attachment structure is able to move relative to the washer as the second part is rotated about the first part.

The disclosed luminaire enables the first part and the second part to be adjusted repeatedly without inadvertently loosening the attachment structure. More specifically, since the washer is arranged to enable relative movement of the attachment structure, the washer enables the first part and the second part to be rotated without loosening the attachment structure.

Preferably, the attachment structure comprises a screw and/or a bolt.

Preferably, the screw is arranged to interact with a nut so as to attach the first part and the second part. Preferably, the washer is arranged to enable the screw to move so as to reduce relative movement between the screw and the nut as the second part is rotated about the first part.

Preferably, the washer comprises a nylon washer.

Preferably, the washer is located between a shoulder of the attachment structure and the first part and/or between a shoulder of the attachment structure and the second part. -2 -

Preferably, the washer is located at least between the attachment structure and the first part.

Preferably, the luminaire comprising a further washer arranged to resist rotation of the second part about the first part.

Preferably, the further washer is located between the first part and the second part.

Preferably, the further washer comprises a compressible washer. Preferably, the further washer comprises a rubber washer and/or a silicon rubber washer.

Preferably, the further washer is arranged to resist rotation of the second part about the first part when in a compressed position.

Preferably, the further washer is arranged to prevent unintentional rotation of the second part about the first part.

Preferably, the coefficient of friction between the washer and the attachment structure is less than the coefficient of friction between one or more of: the first part and the second part; the attachment structure and the first part; the attachment structure and the second part; a/the further washer and the first part; and a/the further washer and the second part.

Preferably, the attachment structure and/or a/the shoulder of the attachment structure comprises a low friction material.

Preferably, the coefficient of friction between the washer and the attachment structure is one or more of: no greater than 0.5; no greater than 0.3; and/or no greater than 0.1.

Preferably, the coefficient of friction between the washer and the first part and/or the second part is one or more of: no greater than 0.5; no greater than 0.3; and/or no greater than 0.1.

Preferably, the attachment structure is arranged such that the attachment structure can be tightened. Preferably, the attachment structure is arranged such that the attachment structure can be tightened in order to alter a force that resists rotation of the second part about the first part; and/or in order to compress the further washer.

Preferably, a/the further washer is located in a recess of the second part. Preferably, the further washer is located between an inner component of the second part and a component of the first part.

Preferably, the recess is sized so as to enable an amount of radial expansion of the first washer.

Preferably, the recess is sized so as to limit an amount of radial expansion of the first washer. -3 -

Preferably, the second part comprises a first, inner, component and a second, outer, component. Preferably, the inner component and the outer component are located to either side of a connecting component of the first part. Preferably, each of the inner component, the outer component, and the connecting component comprise at least one hole, wherein the attachment structure is arranged to pass through the nut via the holes of each component so as to attach the first part to the second part.

Preferably, the attachment structure passes through a single hole of each of the outer component and the connecting component.

Preferably, the attachment structure passes through two holes of the inner component.

Preferably, the attachment structure is arranged such that the second part is able to move translationally relative to the first part.

Preferably, the attachment structure is arranged to resist translational movement of the second part relative to the first part.

Preferably, the attachment structure is moveable by a user so as to compress or decompress the washer and/or a/the further washer. Preferably, the attachment structure is moveable by a user so as to compress or decompress a/the further washer.

Preferably, the attachment structure is moveable by a user so as to alter an amount of slip associated with the washer. Preferably, the attachment structure is moveable by a user so as to alter the degree to which the attachment structure moves relative to the washer as the second part is rotated about the first part.

Preferably, the washer is (substantially) incompressible. Preferably, the washer is arranged not to compress as the user moves the attachment structure.

Preferably, the first part comprises a lamp holder (e.g. a luminaire base) and the second part comprises a lamp (e.g. a luminaire head).

According to another aspect of the present disclosure, there is described a method of adjusting the aforesaid luminaire.

Preferably, the method comprises a computer-implemented method.

According to another aspect of the present disclosure, there is described a computer program product comprising software code adapted when executed to carry out the aforesaid method.

According to another aspect of the present disclosure, there is described a lighting system comprising: one or more luminaires as aforesaid; and one or more computer devices arranged to adjust the luminaires. -4 -

According to another aspect of the present disclosure, there is described an adjustment structure for a luminaire, the adjustment structure comprising an attachment structure arranged to attach a first part of a luminaire to a second part of the luminaire such that the second part is able to rotate about the first part; and a washer arranged to be located between one or more of: the attachment structure and the first part; and the attachment structure and the second part; wherein the washer is arranged to enable the attachment structure to move relative to the washer as the second part is rotated about the first part.

According to another aspect of the present disclosure, there is described a kit of parts for an adjustable luminaire, the kit of parts comprising: the aforesaid adjustment structure; a first part of a luminaire; and optionally, a second part of the luminaire.

According to another aspect of the present disclosure, there is described a kit of parts for an adjustable luminaire, the kit of parts comprising: the aforesaid adjustment structure; a second part of a luminaire; and optionally, a first part of the luminaire.

Optionally, the kit of parts may comprise two or more, different, first parts and/or two or more, different, second parts, the/each first part and the/each second part being attachable to one another.

According to another aspect of the present disclosure, there is described a luminaire that comprises two parts, which parts may be adjusted by pivoting or rotating the luminaire. The luminaire may comprise an element that enables a component of the luminaire to slip about the parts as the luminaire is adjusted. The degree of slip may be alterable, for example by adjusting an attachment mechanism of the luminaire, such as a screw.

According to a further aspect, there is provided a computer program product comprising computer implementable instructions for causing a programmable computer device to carry out the method as described.

The invention extends to methods and/or apparatus substantially as herein described with reference to the accompanying drawings.

Any apparatus feature as described herein may also be provided as a method feature, and vice versa.

Any feature in one aspect of the invention may be applied to other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to apparatus aspects, and vice versa. Furthermore, any, some and/or all features in one aspect can be applied to any, some and/or all features in any other aspect, in any appropriate combination. -5 -

It should also be appreciated that particular combinations of the various features described and defined in any aspects of the invention can be implemented and/or supplied and/or used independently.

The term 'comprising' as used in this specification and claims preferably means 'consisting at least in part of'. When interpreting statements in this specification and claims which include the term 'comprising', other features besides the features prefaced by this term in each statement can also be present. Related terms such as 'comprise' and 'comprised' are to be interpreted in a similar manner.

Brief Description of the Figures

One or more aspects will now be described, by way of example only and with reference to the accompanying drawings having like-reference numerals, in which: Figures la and lb show, respectively, a perspective view and a side on view of a luminaire. Figure 2 shows an exploded view of a part of the luminaire.

Figures 3a and 3b show, respectively, an exploded view and an assembled view of an adjustment structure of the luminaire.

Figure 4 shows a perspective view of a further part of the luminaire. Detailed Description Referring to Figures la and lb, there is shown a luminaire that comprises a first part 10 and a second part 20. The first part and the second part are connected using an adjustment structure 30.

The description below considers embodiments in which the first part comprises a lamp holder (e.g. a luminaire base) 10 and the second part comprises a lamp (e.g. a luminaire head) 20. The lamp typically comprises a lighting element. It will be appreciated that the first part and the second part may comprise other types of component.

The adjustment structure 30 is arranged such that the lamp 20 is able to rotate about the lamp holder 10. Therefore, a user is able to rotate the lamp so that light is emitted from an optical element of the lamp at a desired angle.

The adjustment structure 30 is typically arranged to be removable (and/or to be moveable between a first position, in which the lamp holder 20 and the lamp 10 are connected, and a second position, in which the lamp holder and the lamp are unconnected). With such a structure, the lamp holder may be used with a variety of different lamps. More specifically, a -6 -variety of different types of lamps may be used with a single lamp holder. This leads to a more efficient manufacturing processes and also increases the versatility of the lamp holder.

In some embodiments, the adjustment structure 30 comprises a screw and/or a bolt. For example, the adjustment structure may comprise a 12mm screw of a M2.5 screw. It will be appreciated that the size of the adjustment structure 30 may vary depending on the size of the lamp 20.

In the embodiment shown in the drawings, the adjustment structure comprises a flat-head screw. This enables a user to insert or remove the adjustment structure using a screwdriver.

In some embodiments, the adjustment structure 30 can be tightened to a varying extent (e.g. as with a screw). The tightness of the adjustment structure affects the amount of force required to rotate the lamp 20 of the luminaire about the lamp holder 10. Therefore, a user may loosen the adjustment structure to ease rotation before rotating the lamp. Equally, a user may tighten the adjustment structure to prevent rotation of the lamp after the lamp has reached a desired orientation. Typically, a user (or a manufacturer) will tighten the adjustment structure to a point at which the lamp will not rotate without an external input (e.g. it will not rotate under gravity), but at which a user is able to comfortably rotate the lamp. At such a point, a user does not require any equipment to adjust the lamp.

The lamp 20 is typically arranged to rotate through at least a 900 arc and/or through at least a 180° arc.

A drawback of existing adjustment structures is that a conventional adjustment structure can loosen over time. In particular, regular adjustment of a conventional luminaire can lead to an adjustment structure loosening unintentionally so that a user must frequently tighten the adjustment structure. This is a source of irritation to users who must either live with a loosely connected luminaire or frequently locate a suitable screwdriver.

The present disclosure relates to an adjustment structure that enables adjustment of a luminaire while resisting loosening of the adjustment structure.

The composition of the adjustment structure 30 will now be described with reference to Figures 2, 3a, 3b, and 4. Figure 2 shows an exploded view of the adjustment structure and of the components of the luminaire that interact with the adjustment structure. Figures 3a and 3b show, respectively, an exploded view of the adjustment structure and an assembled view of the adjustment structure. Figure 4 shows a view of an inner component 24 of the lamp 20.

The adjustment structure 30 of this exemplary embodiment comprises: a screw 32, a nut 34, a first washer 36, and a second washer 38. 7 -

The screw 32 fixes together the lamp holder 10 and the lamp 20. Typically, the screw resists translational movement of the lamp relative to the lamp holder, but allows rotational movement of the lamp relative to the lamp holder.

The screw 32 comprises a threaded portion that is arranged to interact with the nut 34 so that the screw can be inserted into the nut. To assemble the luminaire, the lamp 10 and the lamp holder 20 are placed next to each other. The nut is then located to one side of the luminaire and the screw is located to the other side of the luminaire. The screw is moved through the luminaire into the nut, and the screw is tightened to affix the screw and the nut and therefore to connect the lamp and the lamp holder.

Typically, the screw 32 is only partially threaded. The threaded part of the screw may have a smaller diameter than a shoulder 33 of the screw so that the threaded part may be passed through holes in the lamp holder 10 and the lamp 20 of the luminaire with the shoulder 33 then being arranged adjacent (and optionally abutting) the exterior of one of the holes to ensure appropriate placement of the screw in the luminaire. As described in further detail below, the second washer 38 is typically arranged between the shoulder of the screw and the exterior of one of the holes, such that the second washer abuts the exterior of said hole, and the shoulder of the screw abuts the second washer.

The nut 34 interacts with a thread of the screw 32 so that the screw can be inserted into the nut. In this embodiment, the screw is passed through: a hole 23 in an outer component 22 of the lamp 20; a hole 13 in a connecting component 12 of the lamp holder 10; holes 25 in an inner component 24 of the lamp; and then into the nut 34. Therefore, the inner component 24 and the outer component 22 (and the lamp 20) are able to rotate about the connecting component 12 (and the lamp holder 10).

By tightening the screw 32, the nut 34 moves along the thread of the screw. Therefore, the screw is pressed against the outer component 22 of the lamp and/or the shoulder 33 of the screw is pressed against the connecting component 12 and/or the nut is pressed against the inner component 24. The inner component 24 is therefore pulled against the connecting component 12. The friction between adjoining components resists relative rotation of the lamp about the lamp holder (due to friction). It will be appreciated that, as described in further detail below, a first washer 36 is typically arranged between the inner component 24 and the connecting component 12. More generally, washers may be arranged between any two structures, so that (for example) the shoulder of the screw may be pressed against the connecting component via the second washer 38.

Typically, the nut 34 is located in between the inner component 24 of the lamp and the connecting component 12 of the lamp holder 10, so that the nut is not visible from the exterior -8 -of the luminaire. Referring to Figure 4, there is shown a view of the inner component 24 in which a nut recess 28 can be seen. The nut is arranged to fit into this nut recess so that tightening the screw pulls the nut into the recess and thereby secures together the inner component, the connecting component, and the outer component 22.

The screw 32 can be loosened to loosen the connection between the lamp holder 10 and the lamp 20 and to allow rotation, or tightened to tighten the connection between the lamp holder and the lamp to prevent rotation. Further, the screw may be tightened to an intermediate position at which rotation is resisted, but is possible (e.g. so that the lamp does not rotate without an external input, but can be rotated by a user).

It will be appreciated that luminaires may be provided with different componentry; for example, the lamp 20 may be provided with only one of the outer component 22 and the inner component 24. Generally, the screw 32 is arranged to pass through at least one component of the lamp and at least one component of the lamp holder 10 so as to connect the lamp to the lamp holder. Equally, the screw may be replaced (or supplemented) by another attachment structure that is able to hold together the lamp holder 10 and the lamp 20, such as a bolt, a pin or a clip.

The first washer 36 is typically located between the inner component 24 of the lamp 20 and the connecting component 12 of the lamp holder 10.

The first washer 36 typically comprises a compressible washer, that is a washer that is able to compress substantially due to a force imparted by the screw (e.g. by a human turning the screw). Typically, the first washer comprises a rubber washer and/or a silicone rubber washer. The first washer is arranged to be compressible in an axial direction when the screw 32 is tightened and each of the components of the luminaire are pressed together. Where the first washer is unconstrained in the radial direction, this axial compression results in the first washer expanding in the radial direction. As the first washer is pressed into a component of the luminaire by the tightening of the screw, an amount of friction between the first washer and that component increases. This friction resists rotation of the components of the luminaire, and so the use of a compressible washer enables the user to tighten the screw 32 to achieve a desired resistance to rotation. It will be appreciated that a non-compressible washer could be used for the first washer, and tightening the screw would still result in increased friction that resists rotational movement.

Where a compressible washer is used for the first washer 36, the expansion of the first washer in the radial direction may be limited, e.g. by locating the first washer in a recess 26 of a component (such as the connecting component 12 or the inner component 24) of the lamp holder and/or the luminaire. In such a way, the first washer can be arranged to compressible -9 -in the axial direction only until a certain point, e.g. until the diameter of the first washer has increased to be equal to the diameter of the recess. At this point the first washer can no longer expand and therefore further tightening of the screw is prevented. Such an arrangement can be used to further fix the luminaire in a selected position. Furthermore, the force exerted by the first washer acts to press the components of the luminaire together to ensure a tight (and enduring) connection between the components of the luminaire.

The magnitude of the frictional force exerted on the luminaire by the first washer 36 depends on the amount of compression of the first washer (which depends on the tightness of the screw 32). Therefore, the first washer can be used to prevent unintended rotation of the luminaire while enabling intentional rotation (e.g. by tightening the screw 32 such that the first washer is compressed to a desired amount and is exerting a desired force that resists rotation).

The second washer 38 is typically located between the screw 32 and the connecting component 12 (or between the screw and the outer component 22 depending on the implementation). Therefore, as the screw is tightened, the shoulder 33 of the screw is pressed against the second washer 38. The second washer comprises a low-friction washer or a 'slip' washer that enables the shoulder of the screw to slip about the second washer when the lamp 20 is rotated about the lamp holder 10.

With arrangements that do not use the second washer 38, the shoulder 33 of the screw 32 abuts the connecting component 12. The friction between the screw and the connecting component then holds the screw in place as the lamp 20 is rotated about the lamp holder. This causes the nut 34 to rotate relative to the screw as the lamp is rotated so that the adjustment of the lamp can inadvertently loosen the adjustment structure 30.

With the second washer 38 of the present disclosure, the shoulder 33 of the screw 32 is able to slip on the second washer as the lamp 20 is rotated. Therefore, instead of loosening the adjustment structure 30, the rotation of the lamp causes the screw to turn with the nut 34 and to slip about the second washer. Therefore, a user is able to frequently adjust the luminaire without inadvertently loosening the adjustment structure 30. The user is still able to loosen the adjustment mechanism intentionally using a screwdriver (or other adjustment tool).

The second washer 38 is typically selected so that the coefficient of friction between the second washer and the screw 32 is less than the coefficient of friction between the first washer and the lamp holder 10 and/or the coefficient of friction between the first washer and the lamp 20. In some embodiments, the shoulder 33 of the screw comprises a low friction material.

-10 -Typically, the second washer is arranged so that the coefficient of friction between the second washer 38 and the screw 32 (and/or between the second washer and the lamp 20 or the lamp holder 20) is no greater than 0.5, no greater than 0.3, and/or no greater than 0.1.

Typically, the second washer 38 comprises a nylon washer.

The second washer 38 may comprise a low friction material on both sides of the second washer (so that the second washer slips about both of the connecting component 12 and the screw 32). Equally, the second washer may comprise a comparatively high friction material on one side (e.g. adjacent the connecting component). Therefore, the second washer may stay in place relative to the connecting component while the screw slips about the second washer.

It will be appreciated that the second washer 38 may be provided without the first washer 36 and will still provide a benefit (and vice versa). A combination of the first washer and the second washer is particularly beneficial, since the first washer can be used to resist rotation of the lamp 20 about the lamp holder 10 (so that the lamp does not rotate without a user input), while the second washer ensures that such a user input does not inadvertently loosen the adjustment structure 30.

Typically, the lamp 20 (e.g. the inner component 24 of the lamp holder) comprises a recess 26 for the first washer 36. Similarly, typically, the lamp holder 10 (e.g. the connecting component 12 of the lamp) comprises a recess 14 for the second washer 38. Therefore, when the luminaire is assembled, an inner component of the lamp and the lamp holder are separated by the first washer and the lamp holder and the shoulder 33 of the screw 32 are separated by the second washer.

In some embodiments, the lamp holder 10 comprises a power supply (or a connection to the power supply). The adjustment structure (and the holes of the lamp 20 and the lamp holder) may be arranged to connect the lamp and the lamp holder in such a way that the lamp is connected to a power supply of the lamp holder, for example to a 48V power supply and/or to a mains power supply.

The screw 32 (or more generally an attachment structure used to attach the lamp holder 10 and the lamp 20) may comprise a cable guide. For example, a cable may be located in an interior of a screw. Such a cable guide is useable to connect the lamp and the lamp holder (e.g. to connect electronic components of the lamp and the lamp holder) in such a way that cabling is not damaged when the lamp is rotated relative to the lamp holder.

Alternatives and Modifications Various other modifications will be apparent to those skilled in the art. It will be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.

For example, while the detailed description has described an adjustment structure that allows selective rotation of a luminaire, it will be appreciated that such an adjustment structure may also be provided that allows selective translation of a luminaire. For example. the adjustment structure may be tightened to such a degree that it resists unintentional translational movement but may be moved translafionally by a user.

While the detailed description has described the use of a screw and a corresponding nut, the adjustment structure 30 may more generally comprise any attachment structure. For example, instead of a screw, the attachment structure may comprise a bolt, or a (optionally non-threaded) bar that is placed through the holes in the lamp 20 and the lamp holder 10.

The embodiments of the detailed description consider a screw 32 that is internal to the luminaire so that the screw only passes through one hole 23 of the outer component 22 of the lamp 20 and one hole 13 of the connecting component 12 of the lamp holder 10. It will be appreciated that a screw may be provided that passes through two holes of each component. In such an arrangement there may be provided two first washers (e.g. a first washer may be located to either side of the inner component 24) and/or two second washers (e.g. a second washer may be located to either side of the connecting component 12).

The luminaire may be provided as a kit of parts. In particular, the disclosed adjustment structure/mechanism 30 may be provided with the lamp holder 10, with a user being able to connect the lamp holder to a desired (optionally separate) lamp 20 In order to adjust the luminaire, a user rotates the lamp 20 about the lamp holder 10. Equally, the adjustment may be automated. For example, an actuator may be used to rotate the lamp about the lamp holder.

The luminaire may be provided as part of a lighting system; for example a system comprising one or more luminaires and a computer device arranged to control the luminaire(s). Such a computer device may comprise a processor for determining an amount of rotation (or force) to be applied to a luminaire and a communication interface (e.g. a local area network interface) for receiving instructions from a user and/or for transmitting instructions to an actuator that rotates a luminaire.

-12 -Each feature disclosed in the description, and (where appropriate) the claims and drawings may be provided independently or in any appropriate combination.

Reference numerals appearing in the claims are by way of illustration only and shall have no limiting effect on the scope of the claims.

Claims

-13 -Claims 1 An adjustable luminaire, the luminaire comprising: a first part (e.g. a lamp holder); a second part (e.g. a lamp); an attachment structure arranged to attach the first part to the second part such that the second part is able to rotate about the first part; and a washer located between one or more of: the attachment structure and the first part; and the attachment structure and the second part; wherein the washer is arranged so that the attachment structure is able to move relative to the washer as the second part is rotated about the first part.
2. The luminaire of any preceding claim, wherein the attachment structure comprises a screw and/or a bolt.
3 The luminaire of claim 2, wherein the screw is arranged to interact with a nut so as to attach the first part and the second part, preferably wherein the washer is arranged to enable the screw to move so as to reduce relative movement between the screw and the nut as the second part is rotated about the first part.
4. The luminaire of any preceding claim, wherein the washer comprises a low friction washer and/or a nylon washer.
The luminaire of any preceding claim, wherein the washer is located between a shoulder of the attachment structure and the first part and/or between a shoulder of the attachment structure and the second part.
6 The luminaire of any preceding claim, comprising a further washer arranged to resist rotation of the second part about the first part, preferably wherein the further washer is located between the first part and the second part.
7. The luminaire of claim 6, wherein the further washer comprises a compressible washer, more preferably a rubber washer and/or a silicon rubber washer.
8. The luminaire of claim 7, wherein the further washer is arranged to resist rotation of the second part about the first part when in a compressed position.
-14 - 9. The luminaire of any of claims 6 to 8, wherein the further washer is arranged to prevent unintentional rotation of the second part about the first part.
10. The luminaire of any preceding claim, wherein the coefficient of friction between the washer and the attachment structure is less than the coefficient of friction between one or more of: the first part and the second part; the attachment structure and the first part; the attachment structure and the second part; a/the further washer and the first part; and a/the further washer and the second part.
11. The luminaire of any preceding claim, wherein the attachment structure and/or a/the shoulder of the attachment structure comprises a low friction material.
12 The luminaire of any preceding claim, wherein: the coefficient of friction between the washer and the attachment structure is one or more of: no greater than 0.5; no greater than 0.3; and/or no greater than 0.1; and/or the coefficient of friction between the washer and the first part and/or the second part is one or more of: no greater than 0.5; no greater than 0.3; and/or no greater than 0.1.
13. The luminaire of any preceding claim, wherein the attachment structure is arranged such that the attachment structure can be tightened, preferably wherein the attachment structure is arranged such that the attachment structure can be tightened in order to: alter a force that resists rotation of the second part about the first part; and/or compress the further washer.
14. The luminaire of any preceding claim, wherein a/the further washer is located in a recess of the second part, preferably wherein: the further washer is located between an inner component of the second part and a component of the first part; and/or the recess is sized so as to enable an amount of radial expansion of the first washer; and/or the recess is sized so as to limit an amount of radial expansion of the first washer.
15. The luminaire of any preceding claim, wherein the second part comprises a first, inner, component and a second, outer, component, preferably wherein the inner component and the outer component are located to either side of a connecting component of the first part, more preferably wherein each of the inner component, the outer component, and the connecting component comprise at least one hole, wherein the attachment structure is arranged to pass through the nut via the holes of each component so as to attach the first part to the second part.
16. The luminaire of claim 15, wherein the attachment structure passes through a single hole of each of the outer component and the connecting component and/or wherein the attachment structure passes through two holes of the inner component.
17. The luminaire of any preceding claim, wherein the attachment structure is arranged such that the second part is able to move translationally relative to the first part.
18. The luminaire of any of claims 1 to 17, wherein the attachment structure is arranged to resist translational movement of the second part relative to the first part.
19. The luminaire of any preceding claim, wherein the attachment structure is moveable by a user so as to compress or decompress the washer and/or a/the further washer.
20. The luminaire of any preceding claim, wherein the first part comprises a luminaire base and the second part comprises a luminaire head.
21. A method of adjusting the luminaire of any preceding claim.
22. A computer program product comprising software code adapted when executed to carry out the method of claim 21.
23. A lighting system comprising: one or more luminaires according to any of claims 1 to 20; and one or more computer devices arranged to adjust the luminaires.
24. An adjustment structure for a luminaire, the adjustment structure comprising: an attachment structure arranged to attach a first part of a luminaire to a second part of the luminaire such that the second part is able to rotate about the first part; and -16 -a washer arranged to be located between one or more of: the attachment structure and the first part; and the attachment structure and the second part; wherein the washer is arranged so that the attachment structure is able to move relative to the washer as the second part is rotated about the first part.
25. A kit of parts for an adjustable luminaire, the kit of parts comprising: the adjustment structure of claim 24; a first part of a luminaire; and optionally, a second part of the luminaire.