US-12624825-B2 - Drainage for light fixture with movable lens

Abstract

A light fixture is provided, comprising a light fixture housing with a housing sidewall extending circumferentially around a movable lens. The light fixture housing forms an inner space that includes at least one light source for emitting light through the movable lens. The movable lens is arranged on a light output side of the light fixture housing and is movable along the housing sidewall relative to the at least one light source. A sealing element is positioned between the housing sidewall and the movable lens, in order to seal the inner space from the exterior environment outside the light fixture. The movable lens defines a cavity in the housing on the light output side. This cavity is at least partially bounded by the movable lens and the sealing element on its inner side, while remaining open to the exterior on the light output side.

Inventors

• Niels Jørgen Rasmussen

Assignees

• HARMAN PROFESSIONAL DENMARK APS

Dates

Publication Date

20260512

Application Date

20250422

Priority Date

20240523

Claims (20)

1. 1 . A light fixture comprising: a light fixture housing with a housing sidewall extending circumferentially around a movable lens, the light fixture housing forming an inner space including at least one light source for emitting light through the movable lens; the movable lens arranged on a light output side of the light fixture housing and movable along the housing sidewall relative to the at least one light source; a sealing element between the housing sidewall and the movable lens, wherein: the sealing element seals the inner space from an exterior outside the light fixture, and movement of the movable lens modifies a volume of a cavity formed in the housing on the light output side, the cavity being at least partially bounded by the movable lens and the sealing element on an inner side of the cavity and open to the exterior on the light output side; and at least one drainage element extending from the cavity through the housing sidewall for draining accumulated liquid from the cavity.
2. 2 . The light fixture of claim 1 , wherein the at least one drainage element comprises a drainage tube extending from the cavity through the housing sidewall to the exterior of the light fixture, wherein the drainage tube provides a flow channel for the accumulated liquid.
3. 3 . The light fixture of claim 1 , wherein the at least one drainage element comprises a drainage inlet positioned in the cavity to receive the accumulated liquid and a drainage outlet positioned in the housing sidewall to discharge the accumulated liquid, wherein the drainage element has a first end coupled to the drainage inlet and a second end coupled to the drainage outlet.
4. 4 . The light fixture of claim 3 , wherein the drainage inlet is positioned adjacent to the movable lens in the sealing element and configured to move with the movable lens.
5. 5 . The light fixture of claim 3 , wherein the drainage inlet extends through the movable lens.
6. 6 . The light fixture of claim 3 , wherein the sealing element comprises a deformable membrane having a tubular shape extending from a first end of the deformable membrane to a second end of the deformable membrane, wherein: the first end of the sealing element is attached to the movable lens around a circumferential edge of the movable lens, and a second end of the deformable membrane is attached to the housing sidewall.
7. 7 . The light fixture of claim 6 , wherein the second end of the sealing element is attached to the housing sidewall on the light output side of the movable lens.
8. 8 . The light fixture of claim 6 wherein the tubular shape of the sealing element forms an inner space, wherein the inner space is closed by the movable lens on an inner side of the inner space and is open to the exterior on the light output side, and wherein the cavity in the housing is formed by the inner space of the sealing element.
9. 9 . The light fixture of claim 1 , wherein the at least one drainage element comprises a moving end and a fixed end, wherein the moving end of the drainage element is coupled to the movable lens and the fixed end of the drainage element is coupled to the housing.
10. 10 . The light fixture of claim 1 , wherein a second end of the sealing element is attached to the housing sidewall on a light receiving side of the movable lens, wherein the housing sidewall extends circumferentially along the sealing element and partly bounds the cavity.
11. 11 . The light fixture of claim 1 , wherein a drainage inlet of the at least one drainage element is positioned at a surface of the cavity.
12. 12 . The light fixture of claim 11 , wherein the drainage inlet is positioned in an inner half of the cavity on an bottom surface of the cavity.
13. 13 . The light fixture of claim 12 , wherein the at least one drainage element is formed as a separate part from the sealing element.
14. 14 . The light fixture of claim 12 , wherein the at least one drainage element is integrally molded with the sealing element.
15. 15 . The light fixture of claim 1 , wherein the at least one drainage element is positioned on a side surface of the light fixture housing.
16. 16 . The light fixture of claim 1 , wherein the at least one drainage element comprises an elastic tube and/or a foldable bellows.
17. 17 . The light fixture of claim 1 , wherein the light fixture is a moving head light fixture, wherein the inner space is within a head of the moving head light fixture, wherein the movable lens is a zoom lens, which is a last optical element along a light path of the light fixture.
18. 18 . The light fixture of claim 17 , wherein the light fixture comprises a longitudinal optical axis extending through the housing sidewall and a center of the movable lens, and a tilt rotational axis extending through the head, and wherein the at least one drainage element is positioned in the cavity on a plane, which includes the longitudinal optical axis and is perpendicular to the tilt rotational axis.
19. 19 . The light fixture of claim 1 , wherein the at least one drainage element is made of an elastic material.
20. 20 . The light fixture of claim 1 , wherein the drainage element extends through the inner space of the housing.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority benefit of Application No. EP 24177540.2, titled “DRAINAGE FOR LIGHT FIXTURE WITH MOVABLE LENS,” and filed May 23, 2024. The subject matter of this related application is hereby incorporated by reference herein in its entirety. DETAILED DESCRIPTION Technical Field Various examples of the disclosure generally relate to the field of light fixtures. Various examples of the disclosure specifically relate to drainage elements in light fixture housings, more specifically to drainage elements in outdoor light fixtures with moving front lens. BACKGROUND Light fixtures are exposed to various environmental conditions, including rain and moisture. For example, in some light fixtures, the front lens may be movable, for example to provide zoom capabilities. However, the movement of the front lens can create a bucket or cavity in the fixture housing, in which fluid can accumulate. Accumulated fluid can cover the front lens, which degrades the optical properties and results in reduced or distorted light output. Additionally, the accumulated water increases the risk of ingress into the interior of the light fixture, which may damage internal light fixture components. Existing solutions to address fluid accumulation add a fixed transparent glass plate in front of the movable lens to prevent formation of a bucket. However, this additional glass reduces light output, affects the aesthetics of the fixture, and can visibly accumulate condensation or residue. Other existing solutions rely on monitoring and selective drainage movements. For example, fixtures may include sensors to detect rain or water accumulation, and execute a programmed drainage sequence after a certain time or water level is reached. However, this approach depends on power to the fixture and the proper functioning of the sensors and control system. The drainage sequence may also briefly interrupt normal operation of the lighting. SUMMARY Accordingly, there is a need for improved drainage techniques for light fixtures, which can reliably remove accumulated water without impacting normal operation or optical performance of the fixture. This need is met by the features of the independent claims. The features of the dependent claims define further advantageous examples. In the following, the solution according to the present disclosure will be described with regard to light fixture and corresponding light fixture housings, generally referred to as enclosures, including at least one drainage element, wherein it is to be understood that the disclosed techniques can be applied to any kind of enclosure or housing comprising a sealed inner space and a cavity formed in the outer surface of the housing or enclosure. For example, a housing with any kind of cavity defined by a movable or a non-movable outer optical element, such as a lens, may be improved by the described techniques. A light fixture is provided. The light fixture comprises a light fixture housing comprising at least one light source. A housing sidewall of the housing extends circumferentially around a movable lens, in general a movable outer optical element, of the light fixture. In other words, the light fixture housing defines an inner space including the at least one light source for emitting light through the movable lens to the exterior of the light fixture. In various examples, the light fixture housing comprises further optical and/or electrical and/or mechanical light fixture components in the inner space. The light fixture further includes the movable lens, which can be moved, at least partly, within the housing. It is to be understood, that not only strictly axial movement, but other movements of the lens are possible. The housing comprises a housing sidewall, which at least partly surrounds the movable lens. The movable lens is movable along the housing sidewall. In other words, the light fixture comprises a housing with a circumferential sidewall around the perimeter of the movable lens, wherein the movable lens is at least axially movable along the inner surface of the housing sidewall. Both the lens and the housing sidewall may define the same or different central optical and/or mechanical symmetry axis, along the movable lens is transitionally movable. It is to be understood that additionally any arbitrary rotational or non-linear movement can be comprised in the movement of the movable lens. The light source emits light, which is projected forward in a light output direction through the movable lens. The movable lens is arranged on the light output side, in other words as outer or outmost optical element in the light path on the light output side of the light fixture, and therefore exposed to the exterior environment on the light output side. Particularly the lens forms part of the outer surface of the light fixture. On the light output side, which can also be referred to as the light emitting side, the lens may be ex