A luminaire kit

Abstract

A luminaire kit comprising a luminaire part, comprising one or more light emitting elements and a first engagement arrangement, and a cover element, comprising a covering portion for covering the one or more light emitting elements and a second engagement arrangement. The first and second engagement arrangements are together configured to provide a plurality of engagement couples for mechanically engaging the first engagement arrangement with the second engagement arrangement. The plurality of engagement couples comprises a first set of one or more engagement couples configured to provide a mechanical engagement between the first and second engagement arrangements in a first engagement state, and a second set of one or more engagement couples configured to provide a mechanical engagement between the first and second engagement arrangements in a second engagement state, in which at least one mechanical engagement provided by any of the first set has failed.

Description

[0001] A luminaire kit

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to the field of artificial lighting, and in particular to luminaires.

[0004] BACKGROUND OF THE INVENTION

[0005] There is an increasing use of artificial lighting in society. Luminaires are able to emit light for illuminating an environment, such as domestic, industrial, commercial and / or civil environments.

[0006] A typical luminaire will comprise one or more light emitting elements, such as individual LEDs, LED chips or other light emitting components. For improved protection, e.g., from dust, dirt or water, it is common for a luminaire to have one or more cover elements for covering the light emitting element(s). The cover element(s) may be formed separately from the light emitting elements.

[0007] In some approaches, each cover element can be attached and (optionally) detached to / from the remainder of the luminaire. This allows for ease of manufacture and, if detachable, for maintenance, repair or replacement of the light emitting element(s). A respective gasket, e.g., an O-ring, may be positioned between each cover element and the remainder of the luminaire for reducing ingress from foreign material (e.g., dust or water).

[0008] There is an ongoing desire to improve the reliability of the attachment of a cover element to the remainder of the luminaire.

[0009] US 20150260376A1 discloses a lens plate for a LED module.

[0010] DE 102012214334A1 discloses a lighting profile which can be fastened to a base profile.

[0011] EP 4113003A1 discloses a light fixture for diversified lighting with a sliding lampshade and a system for diversified room lighting.

[0012] IT 201900002027A1 discloses an illuminating unit.

[0013] SUMMARY OF THE INVENTION

[0014] The invention is defined by the claims. According to examples in accordance with an aspect of the invention, there is provided a luminaire kit comprising: a luminaire part comprising: one or more light emitting elements; and a first engagement arrangement comprising a plurality of first engagement elements; a cover element comprising: a covering portion for covering the one or more light emitting elements, wherein the covering portion extends in a first plane: a second engagement arrangement comprising a plurality of second engagement elements each configured to mechanically engage with a respective individual first engagement element, each second engagement element comprising a contact region for applying a respective contact force to the respective first engagement element to form an engagement couple, wherein each contact force is a force in a direction perpendicular to the first plane, wherein the plurality of engagement couples comprises: a first set of one or more engagement couples, configured such that, when each second engagement element configured to form an engagement couple belonging to the first set is mechanically engaged with the respective first engagement element, the respective contact force is applied between the first engagement element and the second engagement element configured to form an engagement couple belonging to the first set; and a second set of one or more engagement couples configured such that the contact force is only applied between each second engagement element configured to form an engagement couple belonging to the second set and the respective first engagement element when at least one mechanical engagement of any of the first set of one or more engagement couples has failed.

[0015] In other words, the plurality of engagement couples comprises one or more primary engagement couples, configured to attach the cover element to the luminaire part during an initial period of use of a luminaire assembled from the luminaire kit, and one or more back-up engagement couples, configured to ensure that the cover element remains attached to the luminaire part in the event of failure of any of the primary engagement couples. This reduces a risk of a cover element becoming detached from the luminaire part during use, thus improving a safety of the luminaire.

[0016] The wording “individual” means that, within one engagement couple, there is one first engagement element and one respective second engagement element configured to mechanically engage each other; and none of said first engagement element or said second engagement element is shared with another engagement couple among the plurality of engagement couples.

[0017] In some examples, each of the second set of one or more engagement couples is configured such that, when each of the second engagement elements configured to form an engagement couple belonging to the first set applies the respective contact force to the respective first engagement element, a non-zero gap is defined between the contact region of each second engagement element configured to form an engagement couple belonging to the second set and the respective first engagement element. When at least one mechanical engagement of any of the first set of one or more engagement couples has failed, the nonzero gap is eliminated by a relative displacement between the contact region of each second engagement element configured to form an engagement couple belonging to the second set and the respective first engagement element.

[0018] This reduces a stress experienced by the second set of one or more engagement couples during a period in which each of the first set of engagement couples provides a mechanical engagement between the first and second engagement arrangements, thus improving a likelihood that the second engagement elements are intact at a time of failure of any of the first set of engagement couples.

[0019] In some examples, each second engagement element configured to form an engagement couple belonging to the second set is configured to, when each of the one or more second engagement elements configured to form an engagement couple belonging to the first set applies the respective contact force to the respective first engagement element, position the contact region of the second engagement element configured to form an engagement couple belonging to the second set along a respective axis lying perpendicular to the first plane and intersecting the respective first engagement element.

[0020] In other words, the contact region of each second engagement element belonging to the second set of one or more engagement couples is configured to align with the respective first engagement element when the cover element is attached to the luminaire part by the mechanical engagement of each of the first set of engagement couples. This improves a likelihood that the second engagement element belonging to the second set of one or more engagement couples will mechanically engage with the respective first engagement element in the event of a failure of any of the first set of engagement couples.

[0021] In some examples, each second engagement element comprises a clip configured to clip to the respective first engagement element, wherein, for each clip, a region of each clip defines the contact region of the respective second engagement element.

[0022] In some examples, each first engagement element comprises a surface portion to which the contact region of the respective second engagement element is configured to apply the respective contact force. In other words, each engagement couple is formed by the engagement of a contact region of a second engagement element with a respective surface portion of the respective first engagement element.

[0023] In some examples, each second engagement element configured to form an engagement couple belonging to the second set is configured to, when each of the one or more second engagement elements configured to form an engagement couple belonging to the first set applies the respective contact force to the respective first engagement element, position the contact region of the second engagement element configured to form an engagement couple belonging to the second set along a respective axis lying perpendicular to the first plane and intersecting the respective surface portion.

[0024] This improves a likelihood that the second engagement element belonging to the second set of one or more engagement couples will mechanically engage with the respective surface portion in the event of a failure of any of the first set of engagement couples.

[0025] In some examples, the plurality of first engagement elements comprises a plurality of protrusions provided on the luminaire part, and each respective surface portion is formed on a respective protrusion of the luminaire part.

[0026] In some examples, each second engagement element comprises an aperture configured to fit over the respective protrusion.

[0027] In this way, each protrusion configured to form an engagement couple belonging to the second set may be received within the aperture of a respective second engagement element, but not engaged with an edge of the aperture, when a contact force is applied between each protrusion configured to form an engagement couple belonging to the first set and a respective second engagement element.

[0028] In some examples, each respective surface portion is formed in a same plane. This enables the use of an existing luminaire part in the luminaire kit (in combination with a cover element comprising first and second sets of second engagement elements configured to form the first and second sets of engagement couples respectively).

[0029] In some examples, when the one or more second engagement elements configured to form an engagement couple belonging to the first set are each mechanically engaged to a respective first engagement element, the contact region of each of the one or more second engagement elements configured to form an engagement couple belonging to the first set is located in a different plane to the contact region of each of the one or more second engagement elements configured to form an engagement couple belonging to the second set.

[0030] In some examples, the contact region of each of the one or more second engagement elements configured to form an engagement couple belonging to the first set lies in a same second plane; and the contact region of each of the one or more second engagement elements configured to form an engagement couple belonging to the second set lies in a same third plane, wherein a non-zero distance separates the second plane and the third plane.

[0031] In some examples, the second plane and third plane are parallel to one another. Alternatively, each respective contact region may be formed in a same plane, and each surface portion configured to form an engagement couple belonging to the first set may he in a different plane to each surface portion configured to form an engagement couple belonging to the second set.

[0032] In some examples, the luminaire kit further comprises a sealing element for providing between the cover element and the luminaire part.

[0033] The sealing element may provide a more secure engagement between the first engagement arrangement and second engagement arrangement, by providing an elastic force between the luminaire part and the cover element. The sealing element may further protect components of the assembled luminaire from foreign material (e.g. water and / or dust).

[0034] In some examples, the second engagement arrangement is formed around a periphery of the respective cover element.

[0035] In some examples, the covering portion is a lens plate configured to perform beam-shaping on light emitted by the one or more light emitting elements.

[0036] There is also provided a luminaire assembled from the luminaire kit described above.

[0037] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

[0038] BRIEF DESCRIPTION OF THE DRAWINGS

[0039] For a better understanding of the invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0040] Figure 1 illustrates a perspective front view of a luminaire kit, according to an embodiment of the invention;

[0041] Figure 2 illustrates a perspective side view of the luminaire kit; Figure 3 illustrates the luminaire part and the cover element of the luminaire kit;

[0042] Figure 4 illustrates a portion of a luminaire assembled from the luminaire kit;

[0043] Figure 5 illustrates one embodiment of the engagement between the luminaire part 110 and the cover element 120;

[0044] Figure 6 illustrates the engagement between the luminaire part 110 and the cover element 120, according to another embodiment of the invention;

[0045] Figure 7 illustrates a side view of a portion of the luminaire of Figure 6;

[0046] Figure 8 illustrates a cross-sectional view taken along line A- A of Figure 7; and

[0047] Figure 9 illustrates a cross-sectional view taken along line B-B of Figure 7.

[0048] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] The invention will be described with reference to the Figures.

[0050] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the apparatus, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, systems and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings. It should be understood that the Figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.

[0051] The invention provides a luminaire kit comprising a luminaire part and a cover element. The luminaire part comprises one or more light emitting elements and a first engagement arrangement. The cover element comprises a covering portion for covering the one or more light emitting elements and a second engagement arrangement. The first and second engagement arrangements are together configured to provide a plurality of engagement couples for mechanically engaging the first engagement arrangement with the second engagement arrangement. The plurality of engagement couples comprises a first set of one or more engagement couples configured to provide a mechanical engagement between the first and second engagement arrangements in a first engagement state, and a second set of one or more engagement couples configured to provide a mechanical engagement between the first and second engagement arrangements in a second engagement state, in which at least one mechanical engagement provided by any of the first set of one or more engagement couples has failed.

[0052] Embodiments are at least partly based on the realization that a safety and longevity of a luminaire may be improved by the provision of engagement elements that do not experience stress during a first period of use and that are configured to provide a back-up engagement between a luminaire part and a cover element in the case of failure of any engagement elements used to engage the cover element with the luminaire part during the first period of use.

[0053] Illustrative embodiments may, for example, be employed in lighting systems, for example, outdoor lighting systems. The luminaire kit may be particularly advantageous in outdoor lighting systems, which may experience high levels of ultraviolet light, high temperatures and other external conditions that increase a likelihood of breakage of engagement elements (such as clips provided on a plastic integrated lens plate).

[0054] Figure 1 illustrates a perspective front view of a luminaire kit 100, according to an embodiment of the invention. Figure 2 illustrates a perspective side view of the luminaire kit 100.

[0055] The luminaire kit comprises a luminaire part 110 and at least one cover element 120. The luminaire part comprises one or more light emitting elements 115 (e.g. one or more LEDs) and a first engagement arrangement, described in more detail below. Each cover element comprises a covering portion 125 for covering the one or more light emitting elements of the luminaire part and a second engagement arrangement, described in more detail below. The first engagement arrangement and the second engagement arrangement are configured to engage with one another in order to attach the cover element to the luminaire part (i.e. for assembling the luminaire kit into a luminaire).

[0056] The covering portion 125 of each cover element 120 is configured to allow light to pass through the covering portion. In other words, the covering portion is formed from an optically -transmissive material. For instance, the covering portion may be formed from a polycarbonate.

[0057] In some examples, the covering portion may be configured to control light output by a luminaire assembled from the luminaire kit 100. For instance, the covering portion may comprise a lens plate configured to perform beam-shaping on light emitted by the one or more light emitting elements 115. In Figure 1, the covering portion comprises a plurality of lens elements, each lens element being configured to align with a respective light emitting element of the luminaire part 110 when the cover element 120 is attached to the luminaire part.

[0058] In some examples, the covering portion of each cover element may be integrally formed with the second engagement arrangement of the cover element. For instance, the entire cover element may be formed by injection molding.

[0059] In Figure 1, the luminaire kit 100 comprises four cover elements 120 (three of which have already been attached to the luminaire part 110), each cover element being configured to cover a different set of lighting emitting elements. However, as the skilled person will readily appreciate, the number of cover elements may depend on the design of the luminaire part. For instance, in some examples, a single cover element may be configured to cover all of the one or more lighting elements of the luminaire part.

[0060] In some examples, the luminaire kit 100 may further comprise a sealing element 130 (also known as a gasket) for providing between the cover element 120 and the luminaire part 110. The sealing element may be configured to at least partially fill a gap between the cover element and the luminaire part when the cover element is attached to the luminaire part. In Figure 1, the sealing element is an O-ring; however any suitable sealing element may be used. The sealing element may be formed from an elastomeric material.

[0061] As the skilled person will readily appreciate, the luminaire kit 100 may further comprise other common components of a luminaire. For instance, the luminaire part may further comprise a heatsink, power / driving circuitry, control circuitry, communication circuitry and so on.

[0062] Figure 3 illustrates the luminaire part 110 and the cover element 120 of the luminaire kit in more detail. In particular, Figure 3 illustrates the first engagement arrangement 116 of the luminaire part and the second engagement arrangement 126 of the cover element.

[0063] The first engagement arrangement 116 may comprise a plurality of first engagement elements 117, 118. In Figure 3, each first engagement element comprises a protrusion (in the shape of a hook or a barb) provided on the luminaire part 110.

[0064] The second engagement arrangement 126 comprises a plurality of second engagement elements 127, 128. Each second engagement element is configured to mechanically engage with the first engagement arrangement 116. For instance, each second engagement element may be configured to engage with a respective first engagement element 117, 118. In Figure 3, each second engagement element is provided around a periphery of the cover element 120 and comprises a clip configured to clamp to the first engagement arrangement. In particular, each clip has an aperture configured to engage with a respective protrusion on the luminaire part 110.

[0065] Other suitable structures for providing the first and second engagement arrangements will be readily apparent to the skilled person. For instance, the second engagement elements may alternatively comprise cantilever hooks. In Figure 3, a protrusion 117, 118 is provided on the luminaire part 110 for each second engagement element. Alternatively, a single first engagement element of the first engagement arrangement may be configured to engage with a plurality of second engagement elements. For instance, the first engagement arrangement may comprise a ridge, and the second engagement arrangement may comprise a plurality of cantilever hooks configured to engage with the ridge. Each first engagement element may be formed from a respective portion of the ridge. The plurality of cantilever hooks may comprise a first set of one or more cantilever hooks having a first length and a second set of one or more cantilever hooks having a second, different length, in order to provide the first and second sets of engagement couples described below.

[0066] In examples in which the luminaire kit comprises a sealing element 130, the sealing element may be fitted to the cover element 120 before the cover element is attached to the luminaire part 110. For instance, the cover element may further comprise a ridge onto which the sealing element may be fitted. The luminaire part 110 may comprise a groove (provided on a light output side of the luminaire part and therefore not visible in Figure 3), configured to receive the ridge of the cover element onto which the sealing element is fitted.

[0067] Figure 4 illustrates a portion of a luminaire 400 assembled from the luminaire kit 100. In Figure 4, the first engagement arrangement 116 of the luminaire part 110 is mechanically engaged with the second engagement arrangement 126 of the cover element 120 such that the cover element is attached to the luminaire part.

[0068] Figure 5 illustrates more clearly the engagement between the first engagement arrangement 116 of the luminaire part 110 and the second engagement arrangement 126 of the cover element 120 in the assembled luminaire 400.

[0069] In Figure 5, the aperture 627, 628 of each second engagement element 127, 128 fits over a respective protrusion 117, 118 of the first engagement arrangement, such that each protrusion is received within a respective aperture. Each second engagement element 127, 128 also comprises a contact region 617, 618 for applying a respective contact force F to the first engagement arrangement to form an engagement couple. The contact regions 617, 618 of the second engagement elements 127, 128 illustrated in Figure 5 are each a region of the respective clip at an edge of the aperture in the clip. Each protrusion 117, 118 may additionally comprise a sloped portion, for providing a snap fit between the protrusion and a respective second engagement element 127, 128. Each second engagement element may mechanically engage with the respective protrusion by sliding along the sloped portion until the contact region 617, 627 of the second engagement element has passed the sloped portion.

[0070] Each contact force F is a force in a direction Z, perpendicular to a first plane X-Y in which the covering portion 125 of the cover element 120 extends, and is produced at least in part by the elastic deformation of the first engagement element and second engagement element forming the respective engagement couple. Where present, the sealing element 130 may further contribute to each contact force F, due to the elastic deformation of the sealing element, as described below. Each contact region 617, 618 of the second engagement elements 127, 128 is configured to apply the respective contact force to a respective surface portion 517, 518 of the first engagement arrangement.

[0071] In Figure 5, the contact region 617 of the second engagement element 127 is configured to apply the contact force F to a surface portion 517 of the first engagement arrangement, formed on the protrusion 117. The contact region 618 of the second engagement element 128 is configured to apply the contact force to a surface portion 518 of the first engagement arrangement, formed on the protrusion 118.

[0072] Figure 5 illustrates two different sets of engagement couples. The engagement couple 301 formed by the engagement between the protrusion 117 and the second engagement element 127 belongs to a first set of one or more engagement couples, while the engagement couple 302 formed by the engagement between the protrusion 118 and the second engagement element 128 belongs to a second set of one or more engagement couples.

[0073] The first set of one or more engagement couples 301 is configured such that, when each second engagement element 127 configured to form an engagement couple belonging to the first set is mechanically engaged with the first engagement arrangement 116, the respective contact force F is applied between the first engagement arrangement and the second engagement element 127.

[0074] The second set of one or more engagement couples 302 is configured such that a contact force is only applied between the first engagement arrangement 116 and each second engagement element 128 configured to form an engagement couple belonging to the second set when at least one mechanical engagement of any of the first set of one or more engagement couples has failed. In other words, the first and second engagement arrangements are together configured to provide two engagement states in which the first engagement arrangement 116 is mechanically engaged with the second engagement arrangement 126. In a first engagement state (which may be a default engagement state when the cover element 120 is attached to the luminaire part), a contact force between the first engagement arrangement and the second engagement arrangement is provided only by the first set of engagement couples. In a second engagement state (which is used only if at least one of the engagement couples of the first set has failed), the contact force between the first engagement arrangement and the second engagement arrangement is additionally or alternatively provided by the second set of engagement couples.

[0075] Figure 5 illustrates a situation in which the mechanical engagement of the first set of one or more engagement couples (formed by the engagement between the protrusion 117 and the second engagement element 127) has not yet failed. The contact region 617 of the second engagement element 127 is thus in contact with the surface portion 517 of the first engagement arrangement in order to apply the contact force F in the direction Z.

[0076] In examples in which the sealing element 130 is provided between the luminaire part 110 and the cover element 120, the sealing element may push the cover element 120 away from the luminaire part 110. This results in the contact region 617 of the clip 127 being pressed against the surface portion 517 of the protrusion 117, because the protrusion 117 is within the aperture 617 of the clip 127. This pressing increases the contact force F, and is therefore important for securing the cover element 120 to the luminaire part 110; however, this force also increases a stress of the second engagement elements configured to form an engagement couple belonging to the first set, thus increasing a likelihood of failure of one or more of the engagement couples belonging to the first set.

[0077] As the mechanical engagement of the first set of one or more engagement couples has not yet failed in Figure 5, no contact force is applied between the first engagement arrangement 116 (protrusion 118 in this case) and the second engagement element 128 configured to form an engagement couple belonging to the second set. Instead, a non-zero gap DI is defined between the contact region 618 of the second engagement element 128 and the first engagement arrangement. In other words, the contact region 618 of the second engagement arrangement 128 is not in contact with the surface portion 518 of the first engagement element 118.

[0078] When the respective contact force F is applied by each engagement couple belonging to the first set, the contact region 618 of each second engagement element 128 configured to form an engagement couple belonging to the second set is configured to have a position that will result in the second engagement element 128 applying the respective contact force in response to a failure of the mechanical engagement of the first set of one or more engagement couples. For instance, the contact region 618 may be positioned along a respective axis Z1 lying perpendicular to the first plane X-Y and intersecting the first engagement arrangement.

[0079] In Figure 5, the respective axis Z1 for the contact region 618 intersects the surface portion 518 of the protrusion 118 that the second engagement element 128 is configured to engage with. In other words, the contact region 618 is configured to align with the surface portion 518. In this way, in the event of failure of the engagement couple formed by the protrusion 117 and the second engagement element 127, the contact region 618 will make contact with the surface portion 518, thus preventing the cover element 120 from becoming detached from the luminaire part 110.

[0080] In Figure 5, each surface portion 517, 518 is formed in a same plane (in which axis Y1 lies), while the contact region 617 of the second engagement element 127 is located in a different plane to the contact region 618 of the second engagement element 128. Each of the contact regions configured to form an engagement couple belonging to the first set may lie in a same second plane, while each of the contact regions configured to form an engagement couple belonging to the second set may he in a same third plane, separated from the second plane by a non-zero distance.

[0081] In other words, each protrusion 117, 118 is provided on the luminaire part 110 such that, when the cover element 120 is attached to the luminaire part, the surface portion 517, 518 of each protrusion has a same distance from the first plane X-Y. The second engagement elements are configured such that the contact region 617 of each second engagement element 127 configured to form an engagement couple belonging to the first set has a different distance from the first plane X-Y to the contact region 618 of each second engagement element 128 configured to form an engagement couple belonging to the second set.

[0082] Figures 1 to 5 illustrate a first embodiment, in which the protrusions 117, 118 provided on the luminaire part 110 are identical (and, in particular, provided at a same distance from a light-emitting surface of the luminaire part), and each second engagement element 127 that forms an engagement couple 301 belonging to the first set is different to each second engagement element 128 that forms an engagement couple 302 belonging to the second set (in particular, having a differently -positioned aperture). Advantageously, this allows an existing luminaire part 110 to be covered by a modified cover element (i.e. a cover element configured such that the first and second sets of engagement couples are provided).

[0083] The skilled person will readily appreciate that the first and second sets of engagement couples may alternatively be provided by configuring each contact region of the second engagement arrangement to he in a same plane, and configuring each surface portion of the first engagement arrangement configured to form an engagement couple belonging to the first set to he in a different plane to each surface portion of the first engagement arrangement configured to form an engagement couple belonging to the second set. In this way, an existing cover element may be used to cover a modified luminaire part (i.e. a luminaire part configured such that the first and second sets of engagement couples are provided).

[0084] For instance, Figure 6 illustrates a sectional perspective view of a portion of a luminaire 700, according to another embodiment of the invention. In Figure 6, the first engagement arrangement comprises a first set of protrusions 717, configured to form an engagement couple belonging to the first set, and a second set of protrusions 718, configured to form an engagement couple belonging to the second set. The surface portion 817 of each protrusion 717 belonging to the first set lies in a different plane to the surface portion 818 of each protrusion 718 belonging to the first set.

[0085] The second engagement arrangement comprises a plurality of second engagement elements 727, 728. The contact region 917 of the second engagement element 727 lies in the same plane, in which axis Y2 lies, as the contact region 918 of the second engagement element 728.

[0086] Figure 7 illustrates a side view of a portion of the luminaire 700. Figure 8 illustrates a cross-sectional view taken along line A- A of Figure 7. As Figure 8 shows, each of the second set of protrusions 718 is positioned such that the respective surface portion 818 has a distance D2 from a surface of the luminaire part which is covered by the cover element 720 (i.e. a light-emitting surface of the luminaire part), creating a non-zero gap between the surface portion 818 and the contact region 918 of the second engagement element 728 when a contact force is applied between the protrusion 717 and the second engagement element 727.

[0087] Figure 9 illustrates a cross-sectional view taken along line B-B of Figure 7. Each of the first set of protrusions 717 is positioned such that the respective surface portion 817 has a distance D3 from a surface of the luminaire part which is covered by the cover element 720, where distance D3 is greater than distance D2. Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0088] If the term “adapted to” is used in the claims or description, it is noted the term “adapted to” is intended to be equivalent to the term “configured to”. If the term “arrangement” is used in the claims or description, it is noted the term “arrangement” is intended to be equivalent to the term “system”, and vice versa.

[0089] Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMS:

1. A luminaire kit (100) comprising: a luminaire part (110, 710) comprising: one or more light emitting elements (115); and a first engagement arrangement (116) comprising a plurality of first engagement elements (117, 118, 717, 718); a cover element (120, 720) comprising: a covering portion (125) for covering the one or more light emitting elements, wherein the covering portion extends in a first plane (X-Y): a second engagement arrangement (126) comprising a plurality of second engagement elements (127, 128, 727, 728) each configured to mechanically engage with a respective individual first engagement element, each second engagement element comprising a contact region (617, 618, 917, 918) for applying a respective contact force to the respective first engagement element to form an engagement couple, wherein each contact force is a force in a direction perpendicular to the first plane (X-Y), wherein the plurality of engagement couples comprises: a first set of one or more engagement couples (301), configured such that, when each second engagement element (127, 727) configured to form an engagement couple belonging to the first set is mechanically engaged with the respective first engagement element (117, 717), the respective contact force (F) is applied between the first engagement element and the second engagement element configured to form an engagement couple belonging to the first set; and a second set of one or more engagement couples (302), configured such that the contact force is only applied between each second engagement element (128, 728) configured to form an engagement couple belonging to the second set and the respective first engagement element (118, 718) when at least one mechanical engagement of any of the first set of one or more engagement couples has failed; wherein each of the second set of one or more engagement couples (302) is configured such that, when each of the second engagement elements (127, 727) configured to form an engagement couple belonging to the first set applies the respective contact force tothe respective first engagement element, a non-zero gap (DI) is defined between the contact region (618, 918) of each second engagement element (128, 728) configured to form an engagement couple belonging to the second set and the respective first engagement element (116); and when at least one mechanical engagement of any of the first set of one or more engagement couples has failed, the non-zero gap (DI) is eliminated by a relative displacement between the contact region (618, 918) of each second engagement element (128, 728) configured to form an engagement couple belonging to the second set and the respective first engagement element (116).

2. The luminaire kit of claim 1, wherein each second engagement element (128) configured to form an engagement couple (302) belonging to the second set is configured to, when each of the one or more second engagement elements (127, 727) configured to form an engagement couple belonging to the first set applies the respective contact force (F) to the respective first engagement element, position the contact region (618, 918) of the second engagement element configured to form an engagement couple belonging to the second set along a respective axis (Zl) lying perpendicular to the first plane (X-Y) and intersecting the respective first engagement element.

3. The luminaire kit of claim 1 or 2, wherein each second engagement element (127, 128, 727, 728) comprises a clip configured to clip to the respective first engagement element, wherein, for each clip, a region of each clip defines the contact region of the respective second engagement element.

4. The luminaire kit of any one of claims 1 to 3, wherein each first engagement element comprises a surface portion (517, 518, 817, 818) to which the contact region of the respective second engagement element is configured to apply the respective contact force.

5. The luminaire kit of claim 4, wherein each second engagement element (128, 728) configured to form an engagement couple belonging to the second set is configured to, when each of the one or more second engagement elements (127, 727) configured to form an engagement couple belonging to the first set applies the respective contact force (F) to the respective first engagement element, position the contact region (618, 918) of the second engagement element configured to form an engagement couple belonging to the second setalong a respective axis (Z 1) lying perpendicular to the first plane (X-Y) and intersecting the respective surface portion (518, 818).

6. The luminaire kit of claim 4 or 5, wherein the plurality of first engagement elements comprises a plurality of protrusions (117, 118, 717, 718) provided on the luminaire part, and each respective surface portion (517, 518, 817, 818) is formed on a respective protrusion.

7. The luminaire kit of claim 6, wherein each second engagement element comprises an aperture (627, 628) configured to fit over the respective protrusion.

8. The luminaire kit of any one of claims 4 to 7, wherein each respective surface portion (517, 518) is formed in a same plane.

9. The luminaire kit of claim 8, wherein, when the one or more second engagement elements (127) configured to form an engagement couple belonging to the first set are each mechanically engaged to a respective first engagement element, the second contact region of each of the one or more second engagement elements configured to form an engagement couple belonging to the first set is located in a different plane to the contact region of each of the one or more second engagement elements (128) configured to form an engagement couple belonging to the second set.

10. The luminaire kit of any one of claims 1 to 9, wherein: the contact region of each of the one or more second engagement elements(127) configured to form an engagement couple belonging to the first set lies in a same second plane; and the contact region of each of the one or more second engagement elements(128) configured to form an engagement couple belonging to the second set lies in a same third plane, wherein a non-zero distance separates the second plane and the third plane.

11. The luminaire kit of any of claims 1 to 10, further comprising a sealing element (130) for providing between the cover element (120) and the luminaire part (110).

12. The luminaire kit of any one of claims 1 to 11, wherein the second engagement arrangement is formed around a periphery of the respective cover element.

13. The luminaire kit of any one of claims 1 to 12, wherein the covering portion (125) is a lens plate configured to perform beam-shaping on light emitted by the one or more light emitting elements.

14. A luminaire (400, 700) assembled from the luminaire kit according to any one of claims 1 to 13.

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