JP7621865B2 - Long lighting fixtures - Google Patents

Description

The present invention relates to improvements to long lighting fixtures that are attached to a mounting portion such as a ceiling, and in particular to long lighting fixtures that have a metal fixture support and a resin light-diffusing cover.

Conventionally, long lighting fixtures that use multiple LED light-emitting elements arranged in a line have been known as long lighting fixtures that are attached to a mounting portion such as a ceiling. Such lighting fixtures are configured, for example, by housing a long lighting body in a long housing and covering the lighting body with a translucent cover, for example a translucent milky white synthetic resin cover that has light diffusing properties. In addition, the lighting body is, for example, a long printed wiring board on which multiple light sources such as LED light-emitting elements are arranged in a line at predetermined intervals.

Such long lighting fixtures are equipped with a metal support base and a light-diffusing translucent resin cover. When the fixture is turned on, it generates heat, causing the lighting fixture base and resin cover to expand due to heat. The difference in the expansion coefficients of metal and resin causes the following problems, so measures that take into account the difference in the expansion coefficients of the two materials are required.

That is, in the case of a fixture having end members 12, 12 on both ends of a lighting fixture support 11 and a translucent cover 13 between the end members 12, 12 as shown in Fig. 1(a), a gap 14 is provided between the two members when the lighting is off, taking into consideration the difference in expansion coefficients (several mm) so that excessive pressure is not applied to the contact surfaces of the end members 12, 12 and the cover 13 when the light is turned on and the resin translucent cover 13 expands significantly compared to the metal support 11. Figure 1(b), which shows a schematic internal structure of the lighting fixture, shows the relationship between the base 15 of the metal lighting fixture body and the resin light-diffusing translucent cover 13. The base 15, which is the main part of the metal fixture body, is a single metal plate member with its central part 15a and both ends 15b, 15b integrated together, and below that, hooks 16, 16 integrated with the end members 12, 12 extend from bottom to top and engage with the opening between the central part 15a and both ends 15b, 15b of the base 15, engaging with both ends 15b, 15b of the base 15 so as to sandwich them. When the lighting fixture is turned on and the translucent cover 13 is heated, the translucent cover 13 expands and becomes longer as shown in Figure 1 (c), and both ends abut against the end members 12, 12, making the gap 14 invisible. In this way, defects are prevented from occurring at the abutting surfaces of the end members 12, 12 and the end faces of the cover 13, but since the gap 14 is visible when the light is off, it is not desirable not only in terms of appearance but also in terms of the ingress of dust.

There has been a demand to eliminate this gap from a design perspective, and a simple method for eliminating the gap is known in which the end member is provided with a range of movement that corresponds to the expansion difference of the translucent cover when the LED lighting device is in use, eliminating the gap between the end member and the resin translucent cover, and furthermore, a place where the end member and the translucent cover fit together is provided to simply fix them together and eliminate the gap in the outer shell. (Patent Document 1)

Another conventional method involves completely fixing the resin translucent cover and end members by gluing or welding, and then fixing the translucent cover and metal support base by a different method. However, this method has the drawback of being more complicated due to the increased number of processing steps and components.

JP 2019-21441 A

In the lighting fixture of Patent Document 1, the end member fixed to the metal fixture body with screws is provided with a range of motion to accommodate the difference in thermal expansion when the LED lighting fixture is in use, and the end member and the translucent cover are combined to be able to slide along the length to absorb the expansion allowance, and further, the end member and the translucent cover are provided with a fitting point to simply fix them together, eliminating gaps in the outer shell. However, because the resin end member and the resin translucent cover are assembled as separate members with a range of motion, the structure is complex and there are problems with the rigidity of the entire lighting fixture.

In addition, a method in which the resin translucent cover and end member are completely fixed and the translucent cover and metal part of the device body are fixed in a different way has the drawback of being more complicated due to the increased number of processing steps and component parts.

In view of the above, the object of the present invention is to provide a long lighting fixture that has a simple and robust structure and can prevent problems caused by differences in the thermal expansion coefficients of the metal and resin parts.

In order to solve the above problems, the long-length lighting fixture of the present invention is a lighting fixture that includes a long metal support base, a resin molded structure supported by the support base, a long semi-cylindrical light diffusion cover that covers the upper space of the support base and diffuses the illumination light emitted from the light-emitting elements arranged in a row in the length direction on the support base, and a lighting fixture body equipped with end members that close both ends of the light diffusion cover, in which the lighting fixture body is assembled to the support base so that it can slide in the length direction, and a clearance gap that absorbs the deviation in length caused by the difference between the thermal expansion coefficient of the lighting fixture body and the thermal expansion coefficient of the support base is provided between the support base and the end member to allow the lighting fixture body to slide, and prevents the occurrence of a gap between the light diffusion cover and the end member due to temperature changes.

Any known structure can be used to combine the lighting fixture body with the support base so that it can slide in the longitudinal direction. For example, the lower edge of the side of the light diffusion cover (hereinafter simply referred to as the cover) can be combined with the longitudinal side edge of the support base like a rail so that it can slide freely.

A structure for holding the lighting fixture body, which is slidably mounted on the support base, while limiting the range of longitudinal movement relative to the support base due to differences in thermal expansion coefficients, i.e., a thermal expansion absorption mechanism that provides a gap to absorb the length deviation caused by expansion between the metal support base and the lighting fixture body, which is a resin structure, can be achieved by providing the support base with at least one engaging portion spaced apart in the longitudinal direction, and providing the resin molded structure with at least one engaging member (preferably a pair) that engages with this engaging portion with play approximately equal to the magnitude of the length deviation caused by the difference in expansion coefficients, and absorbing the length deviation with that play. Here, approximately equal means the same or greater than the length deviation corresponding to the difference in expansion coefficients, and does not include a length less than the corresponding length.

The engaging portion may be a bridge portion formed between both longitudinal ends of the support base and an opening provided at a position away from both longitudinal ends, and the engaging member may be a pair of hook members with a substantially U-shaped cross section that are provided upward under the support base so as to sandwich the bridge portion with some play in the longitudinal direction, and the play may be substantially equal to the magnitude of the length difference.

Alternatively, the engagement portion may be an opening provided at a position spaced inward from both longitudinal ends of the support base, and the engagement member may be an upwardly protruding member that is fitted into the opening below the support base with some play in the longitudinal direction, and the play may be approximately equal to the magnitude of the length deviation.

It is preferable that the clearance, i.e., the gap for absorbing the deviation in length during expansion, is provided at the fitting portion between the end member integrated with the cover and the support base.
Furthermore, to improve the design, a non-light-transmitting member can be added to the underside of the end member. In this case, this non-light-transmitting member can be fixed to the metal support base side, and the gap between the end member and the non-light-transmitting member can be provided to absorb the difference in length due to the expansion difference, thereby forming a thermal expansion absorption mechanism.

According to the present invention, in a long lighting fixture, a metal support base and a plastic lighting fixture body are slidably combined, and a gap is provided between the two to absorb the deviation in length caused by the difference in thermal expansion coefficients. This prevents the occurrence of gaps between the light diffusion cover of the lighting fixture body and the end members during thermal expansion, and prevents the occurrence of problems caused by the difference in thermal expansion coefficients between the metal and plastic parts with a simple and sturdy structure.

1 is a schematic diagram showing a conventional lighting device, in which (a) is a side view when not lit, (b) is a cross-sectional view thereof, and (c) is a cross-sectional view when expanded. 1A is a schematic diagram showing a lighting device according to an embodiment of the present invention, in which (a) is a side view when not lit, (b) is a cross-sectional view thereof, (c) is a cross-sectional view thereof when lit and expanded, (d) is a schematic diagram showing a lighting device according to another embodiment of the present invention, in which the cross-sectional view thereof is not lit, and (e) is a cross-sectional view thereof when expanded. FIG. 1 is a perspective view showing an embodiment of the present invention; FIG. 4 is an exploded perspective view showing the embodiment of FIG. 3 in an exploded state; FIG. 5 is an enlarged perspective view showing the inside of one end member by cutting a part of the light diffusion cover of FIG. 4 in the embodiment; 1A is a view of an end member according to the embodiment, and FIG. 1B is a partially enlarged view of the end member. 1A is a side view of the embodiment when not lit, FIG. 1B is a longitudinal sectional view of the embodiment along the length direction, and FIG. 1C is a transverse sectional view of the embodiment when viewed from above. 1A is a side view of the lamp according to the embodiment when it is inflated and illuminated, FIG. 1B is a longitudinal sectional view of the lamp, and FIG. 1C is a transverse sectional view of the lamp as viewed from above. FIG. 2 is a partially enlarged cross-sectional view showing the details of the lower part of the end member and the light-non-transmitting member thereunder in the embodiment;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a long-length lighting fixture according to the present invention will be described with reference to the drawings.
An outline of an embodiment of the present invention is shown in Fig. 2. As shown in Fig. 2(a), the long lighting fixture of the present invention is provided with a long semi-cylindrical light diffusion cover 23 that covers the upper space of a lighting fixture support 21 including a metal support base that supports the entire lighting fixture and diffuses illumination light emitted from light-emitting elements that are aligned in the length direction on the support base, and end members 22, 22 that close both ends of the light diffusion cover 23, and the light-transmitting cover 23 and the end members 22, 22 are joined at joining surfaces 24 with no gaps. At normal temperature when the lighting fixture is not turned on, as shown in Figure 2 (b), a pair of hooks 26, 26 that extend longitudinally below the support base and clamp both ends 25b, 25b of the base in the longitudinal direction are located beneath end members 22, 22 connected to both ends of a light-transmitting cover 23 that is placed so as to be freely slidable in the longitudinal direction, which is the left-right direction in Figure 2, on a support base having a base central portion 25a and both ends 25b, 25b of the base, with clearance gaps 28, 28 provided below the support base to absorb any misalignment in length resulting from the difference in thermal expansion coefficient between the lighting fixture body 22+23 and the support base 21, and face each other with a gap 28 longitudinally inwardly of both ends 25b, 25b of the base. When the lighting fixture is turned on and heated, as shown in FIG. 2(c), due to the difference in thermal expansion coefficient between the lighting fixture body 22+23 and the support base 21, the lighting fixture body 22+23 extends in the longitudinal direction more than the support base. As a result, the hooks 26, 26 move outward in the longitudinal direction by the amount of the extra extension in the longitudinal direction, and the gap absorbs the difference in length, eliminating the play gaps 28, 28. Instead, gaps 29, 29 are created on the longitudinal outside of both ends 25b, 25b of the base.

Since these gaps 28, 28, 29, 29 are all located below the support base inside the lighting fixture support 21, they can be made invisible from the outside by a covering member (described later) fixed or connected to the support base.

The above Figs. 2(a), (b) and (c) show an embodiment in which a pair of hooks 26, 26 with a roughly U-shaped cross section clamps both ends 25b, 25b of the base from below with play 28, 28, 29, 29 in the length direction. However, as another configuration with a similar effect, as shown in Figs. 2(d) and (e), protruding members 56, 56 connected to end members 22, 22 may be provided facing upward so as to fit into the opening between the base center 55a and both ends 55b, 55b of the base from below with play 58, 58, 59, 59 in the length direction. The play may be approximately equal to the magnitude of the length difference.

The specific structure of the embodiment in FIG. 2 will be described in detail below with reference to FIG. 3 to FIG. 9. FIG. 3 is a perspective view showing its appearance, in which a translucent cover 33 with a U-shaped cross section having a top surface 33a and a side surface 33b is placed on a support base 35, and is combined with a pair of end members 32 attached to both ends in the longitudinal direction thereof to be able to slide on the support base 35 by a slight distance in the longitudinal direction (a length corresponding to the difference in expansion length due to the difference in the thermal expansion coefficients; for example, 2 to 3 mm).

Figure 4 shows the lighting fixture of Figure 3 in an exploded view. The support base 35 has rails 35c, 35c on its side edges that support the translucent cover 33 in a slidable manner in the length direction (cover sliding parts 33d, 33d formed on the lower end of the side surface 33b of the translucent cover 33 slidably engage with each other), and a pair of openings 35d, 35d is provided between the center part 35a and both ends 35b, 35b that form the bridge part. The pair of end members 32, 32 connected to both ends of the translucent cover 33 are integrally connected at their lower parts to the hook members 36, 36 via the connecting parts 37. The hook members 36, 36 are composed of hook parts 36, 36 that hold the bridge parts 35b, 35b with some play in the length direction and rising parts 36a, 36a that rise up opposite the hook parts, forming a hook member with a substantially U-shaped cross section in the length direction. (See Figures 7, 8, and 9)

Under the support base 35, non-light-transmitting members 31, 31 are provided which are integrally connected to the lower part of the end members 32, 32. The non-transmitting members 31, 31 include a bottom cover 31b which covers the hook portions 36, 36 from below, a side cover 31c which covers them from the sides, and an end cover 31d which covers them from the outside in the longitudinal direction, covering them from three sides as a screen, and also include a pair of locking portions 31a, 31a for each opening 35d which fits into the respective side edges of a pair of openings 35d, 35d of the support base 35, 35 from below and is connected in an immovable state. This is a decorative component provided to improve the design quality of the entire lighting fixture, and since the non-transparent components 31, 31 are fixed to the support base 35, when the lighting fixture is turned on and thermal expansion occurs, the expansion length of the resin structure 23+32 including the end members 32, 32 expands longer than that of the support base 35 due to the thermal expansion of the translucent cover 33, creating gaps (40, 41, 42 in Figure 9) between the end members 32, 32 that correspond to the difference in length caused by the difference in thermal expansion coefficients.

Next, the state of connection between the translucent cover 33 and the end members 32, 32 will be described with reference to Figures 5 and 6. At the lower end of the side surfaces 33b, 33b of the translucent cover 33, protrusions 33c, 33c that protrude toward the inside of the cover over the entire length are provided parallel to the cover sliding parts 33d, 33d, and the ends of these protrusions 33c, 33c and the end of the translucent cover 33 are fitted to the outside of the frame part 32a that protrudes in a square shape on the inside of the end member 32, and the protrusions 33c are fitted and engaged in the end member engagement parts 32c, 32c, which are gaps formed between the lower part of the frame part and the sub-frame parts 32b, 32b that protrude inwardly parallel to the frame part 32a below it. The engaging portions 32c, 32c have slopes 32d, 32d (Fig. 6b) that rise from the underside of the frame portion 32a and get higher the further inward. The ends of the projections 33c, 33c of the light-transmitting cover 33 are pressed into the gap between the slopes 32d, 32d on the underside of the frame portion 32a and the upper surface of the sub-frame portions 32b, 32b, thereby fixing and joining the light-transmitting cover 33 to the end member 32.

The configuration and operation of the thermal expansion absorption mechanism that absorbs the deviation in length caused by the difference in the thermal expansion coefficient in a lighting fixture constructed in this manner will be described in detail below with reference to Figures 7 to 9. Figure 7 shows the state of the lighting fixture according to the above embodiment when it is not lit, that is, at room temperature when there is little difference in thermal expansion between the metal part and the resin part, where (a) is a side view, (b) is a central vertical cross-sectional view along the length direction, and (c) is a cross-sectional view looking down from above on the support base with the translucent cover cut on a horizontal plane. In this state, there is no difference in the thermal expansion length between the metal support base 35a, 35b and the resin translucent cover 33 and end members 32, 32, so as shown in Figure 7 (b), the rising parts 36a, 36a of the hook members that engage with the bridge parts (engagement parts) 35b, 35b of the support base abut against the bridge parts 35b, 35b from the outside toward the inside, and gaps 38, 38 are created between the bridge parts 35b, 35b and the hooks 36, 36 due to play when not lit. At this time, as shown in Figures 7 (a) and (b), the end faces of the end members 32, 32 and the end faces of the non-translucent members 31, 31 are flush with each other.

Figure 8 shows the state of the lighting fixture according to the above embodiment when it is turned on, that is, when there is a difference in thermal expansion between the metal part and the resin part, (a) is a side view, (b) is a central longitudinal section along the length direction, and (c) is a transverse section of the support base cut by a horizontal plane of the translucent cover. In this state, there is a difference in the expansion length due to thermal expansion between the metal support base 35a, 35b and the resin translucent cover 33 and end members 32, 32, so as shown in Figure 8 (b), the hooks 36, 36 that engage with the bridge parts (engagement parts) 35b, 35b of the support base abut against the bridge parts 35b, 35b from the inside to the outside, and gaps 39, 39 are created between the bridge parts 35b, 35b and the rising parts 36a, 36a of the hook members due to play when the light is turned on. At this time, as shown in Figures 8(a) and (b), the end faces of the end members 32, 32 protrude outward from the end faces of the non-transparent members 31, 31 by an amount equal to the difference in expansion.

9 is a partially enlarged cross-sectional view of the lower end of the above embodiment of the lighting fixture of the present invention, showing the positional relationship between the bridge portion 35b and the hook member 36 in an enlarged manner. As shown in FIG. 9, between the bridge portion 35b of the support base and the hook member 36, there are clearance gaps 38', 39' in the longitudinal direction to absorb the deviation in length caused by the difference between the thermal expansion coefficient of the lighting fixture body and the thermal expansion coefficient of the support base. As described above, as the lighting fixture body expands more, the hook member 36 moves to the left in the figure, the clearance 38' on the hook 36 side becomes smaller, the clearance 39' on the rising portion 36a side becomes larger, and the clearances 40, 41, 42 between the lower portion of the end member 32 and the end face cover 31d of the non-transparent member 31 become smaller. Figure 9 shows the gaps 38', 39' in the process of changing from the unlit state (Figure 7) to the lit state (Figure 8), with the end face of the end member 32 beginning to shift outward from the end face of the end face cover 31d of the non-transparent member 31.

In this way, when the temperature rises due to the lighting of the lighting fixture and the resin part thermally expands more than the metal part, the hook parts 36, 36 fixed to the structure on the resin side are engaged with the metal engagement part 35b with some play, so the translucent cover 33 does not stretch in the length direction together with the end member 32 and cause a malfunction. Also, when the temperature drops due to the lighting fixture being turned off and the translucent cover 33 shortens, the translucent cover 32 is fixed to the end member 32, and the hook parts 36, 36 fixed to the structure on the resin side are engaged with the metal engagement part 35b with some play, so both the translucent cover 33 and the end member 32 contract and become shorter, and no gap that would mar the appearance of the lighting fixture is formed between the translucent cover 33 and the end member 32.

Although one embodiment of the lighting fixture of the present invention has been described above, it goes without saying that the present invention is based on the technical ideas as described in the claims and is not limited to the embodiment. For example, the structure for combining the lighting fixture body with the support base so that it can slide in the length direction may not be the same as the above embodiment in which a rail is combined with a projection extending in the length direction so that it can slide, but may be, for example, a rail-shaped part formed on the support base and a sliding part that slides on the rail-shaped part or a rolling part that rolls on the lower end of the translucent cover (in this sense, in the present invention, "sliding" has a broad meaning including sliding and rolling). In addition, in the above embodiment, the mechanical "gap" is used as a thermal expansion absorption mechanism to absorb the deviation in length, but this "gap" should not necessarily be interpreted as a gap as a space, and for example, the mechanical space may be filled with a soft elastic material such as a sponge. Alternatively, the hook member with a generally U-shaped cross section used in the above embodiment is made of a highly rigid material (e.g., hard resin) and faces the bridge portion (engagement portion) of the undeformable metal support base with a gap (play), but the gap does not necessarily have to be a space, and in short, it is sufficient if the hook member is combined with the engagement portion with some play, so it may be engaged without a gap with some elasticity, for example. Specifically, the hook member may be made of rubber or elastomer and engaged with the support base without a mechanical gap. In that case, the "play gap" defined in the claims includes the deformable portion of the rubber or elastomer as play, and is included in the category of play gap.

LIST OF SYMBOLS 11 Lighting fixture support 12 End member 13 Light diffusing cover, translucent cover 12+13 Lighting fixture body 14 Gap taking into account difference in expansion coefficient 15 Base, support base 15a Center of base 15b Both ends of base, engagement portion 16 Hook 21 Lighting fixture support 22 End member 23 Translucent cover 24 Gap-free joining surface between translucent cover and end member 25a Center of base 25b Both ends of base, engagement portion 26 Hook, engagement member 31 Non-transparent member, non-light-transmitting member 31a Locking portion to support base 31b Bottom cover of non-transparent member 31c Side cover of non-transparent member 31d End cover of non-transparent member 32 End member 32a End member frame portion 32b End member sub-frame portion 32c End member fitting portion 33 Translucent cover 33a Upper surface of translucent cover 33b Side surface of translucent cover 33c Cover protrusion 33d Cover sliding portion 35 Support base 35a Center portion of base 35b Engagement portion, bridge portion 35c Cover sliding rail portion 35d Opening 36 Hook, hook member 36a Rising portion of hook member 37 End member connecting portion 38 Gap due to play when not lit 38' Gap due to play on the side when not lit 39 Gap due to play when lit 39' Gap due to play on the side when lit 40 Gap between end member and non-transparent member 41 Gap between end member and non-transparent member 42 Gap between end member and non-transparent member 55a Center portion of base 55b Both ends of base, engagement portion 56 Protruding member, engagement member 58 Gap due to play when not lit 59 Gap due to play when lit

Claims (3)

A long lighting fixture comprising a long metal support base, and a lighting fixture body which is a resin molded structure supported on the support base and which includes a long semi-cylindrical light diffusion cover which covers an upper space of the support base and diffuses illumination light emitted from light emitting elements which are arranged in a row on the support base in the length direction, and end members which close both ends of the light diffusion cover, the lighting fixture body being assembled to the support base so as to be slidable in the length direction, and a clearance gap which absorbs a deviation in length caused by a difference between the thermal expansion coefficient of the lighting fixture body and the thermal expansion coefficient of the support base being provided between the support base and the end members of the lighting fixture body ,
At least one engaging portion is provided on the support base, and at least one engaging member is provided on the end member of the resin molded structure, the engaging member being engaged with the engaging portion in a longitudinal direction with a play substantially equal to the length deviation ,
a non-light-transmitting member located below the end member is fixed to the support base, and a clearance gap approximately equal to the length deviation is provided between the non-light-transmitting member and the resin molded structure;
In this long lighting fixture, the non-light-transmitting member also serves as a covering member for concealing the play gap so that it cannot be seen from the outside . 2. The lighting fixture as described in claim 1, wherein the engaging portion is a bridge portion formed between both longitudinal ends of the support base and a hole portion provided at a position spaced inward from the both longitudinal ends, and the engaging member is a hook member having an approximately U-shaped cross section and provided upwardly below the support base so as to clamp the bridge portion in the longitudinal direction with play approximately equal to the length deviation . 2. A lighting fixture as described in claim 1, wherein the engaging portion is a hole provided at a position spaced inward from both longitudinal ends of the support base, and the engaging member is an upwardly protruding member that is fitted into the hole under the support base so as to face the hole in the longitudinal direction with play approximately equal to the length deviation.