Illumination – Light source and modifier – Adjustable or repositionable modifier
Reexamination Certificate
2001-07-12
2002-05-14
Cariaso, Alan (Department: 2875)
Illumination
Light source and modifier
Adjustable or repositionable modifier
C362S293000, C362S322000, C359S813000
Reexamination Certificate
active
06386737
ABSTRACT:
The invention relates to an effect wheel rotation system, having a base and at least one effect wheel which is coupled thereto and can be rotated about an axis of rotation by means of a drive, the axis of rotation being arranged offset with respect to an optical axis and the effect wheel having at least one optical element which can be rotated into the region of the optical axis.
Effect wheel rotation systems of this type, which are also known as gobo rotation systems, are used primarily in stage lighting engineering. The effect wheels usually have in their outer region a multiplicity of apertures which lie next to one another in the circumferential direction and in which various optical elements are arranged, such as for example colour filters or diaphragm wheels. The effect wheel is mounted so that it can rotate about an axis, the distance of this axis from the optical axis of the effect wheel rotation system being equal to the distance between the axis of rotation of the effect wheel and the centre point of its apertures. It is thus possible for every optical element of the effect wheel to be rotated into the optical axis, so that a light beam can be influenced in various ways by the effect wheel rotation system. The base serves as a support for the effect wheel rotation system and may, for example, be a mounting plate for attaching the effect wheel rotation system to a spotlight or scaffold. However, it may also be a direct component of a spotlight or scaffold.
A large number of effect wheel rotation systems are known. For example, U.S. Pat. No. 5,113,332 describes an effect wheel rotation system with a plurality of effect wheels which lie one behind the other in the direction of the optical axis, are mounted so that they can rotate about a common centre axis and in their outer region have apertures holding different optical elements in order to produce different patterns. Each of these effect wheels has one aperture without an optical element. When an optical element of an effect wheel is rotated into the region of the, optical axis of a light beam, the clear apertures of the other effect wheels can be pivoted into the region of the optical axis, so that only one optical element is influencing the light beam. Furthermore, the optical elements are mounted rotatably in the effect wheel. As soon as they are rotated into the region of the optical axis, they can be rotated by means of a drive. This system has the drawback that the optical elements can only be rotated by the drive when they have reached the region of the optical axis. It is therefore not possible for the optical element to enter the region of the optical axis in a predetermined position. However, this is of particular interest if not only the colour but also the contour of the light beam is to be influenced using the optical elements or if an image is to be projected via the optical element.
U.S. Pat. No. 5,537,303 has disclosed an effect wheel rotation system in which this problem does not exist. It has an effect wheel, in the outer region of which optical elements are rotatably mounted. The optical elements are provided with toothed rings which each engage in a gearwheel which is mounted so that it can rotate about the centre axis of the effect wheel. The effect wheel and the gearwheel can be rotated independently of one another about the same axis. The two components are rotated by means of separately controlled drives. However, this structure has the drawback that each optical element has to be rotatably mounted and has to be provided with a toothed ring. Therefore, this structure is complex and expensive.
By contrast, the present invention is based on the object of avoiding the abovementioned drawbacks and of providing a simple and inexpensive effect wheel rotation system in which at least one optical element can be rotated about its own axis and can be pivoted into the optical axis of the effect wheel rotation system.
In an effect wheel of the type described in the introduction, this object is achieved by the fact that the effect wheel, independently of a rotation about the axis of rotation, can be rotated about the optical axis.
Rotation about its own axis of rotation in this case leads to an optical element which is to influence the light beam being rotated into the optical region. Since the effect wheel can be rotated about the optical axis, the optical element which has been pivoted into the region of the optical axis can be rotated about the optical axis and therefore—provided that the optical axes of the optical element and the effect wheel rotation system lie on top of one another—about its own optical axis.
One advantage of this system according to the invention over the prior art consists in the fact that only the effect wheel has to be drivable about two different axes. Therefore, the number of moving parts in the system always remains constant, irrespective of how many optical elements are on the effect wheel. In addition to the ensuing advantage of simple production at reduced costs, the reduced number of moving parts leads to a further advantage with regard to the susceptibility of the system to faults. In addition, the type and size of optical elements which can be used in the effect wheel are not restricted by mechanical elements, such as for example a toothed ring, which has hitherto been required for rotation of the optical elements about their own axis. This inevitably results in the further advantage that the number of optical elements can be selected as desired. Finally, it is possible to allow an optical element to rotate, away from the centre by a specific radius, about the optical axis of the effect wheel rotation system if, in this case, the distance of the axis of rotation of the effect wheel from the optical axis is unequal, by this very radius, to the distance between the axis of rotation of the effect wheel and the centre point of the aperture for the optical element and the optical axis of the optical element.
In a simple configuration of the invention, the axis of rotation of the effect wheel is its centre axis, so that in the case of a circular effect wheel all the optical elements which are arranged next to one another, at identical distances from the centre axis, in the circumferential direction can be pivoted into the same region of the optical axis of the effect wheel rotation system.
In a particular embodiment, the effect wheel rotation system has a rolling bearing arrangement with at least two bearing shells which can rotate relative to one another about the optical axis, a shaft which bears the effect wheel being connected to one bearing shell by means of a connecting element and it being possible for the shaft to roll along the other bearing shell.
If the bearing shell which is connected to the shaft is driven, the effect wheel is as a result rotated about the optical axis of the effect wheel rotation system. At the same time, the effect wheel is rotated about its centre axis as a result of the shaft connected thereto rolling along the other bearing shell of the rolling bearing. This rotary movement can be counteracted if both bearing shells are fixedly connected to one another or are driven at the same angular velocity, so that there is no relative movement between the bearing shells. If the other bearing shell is driven in the opposite direction, the angular velocity produced by the rolling movement is increased further. Therefore, in this embodiment the relative movement between the bearing shells of the rolling bearing arrangement is utilized.
Numerous design embodiments are conceivable in which the two bearing shells of the rolling bearing arrangement may be part of one rolling bearing or may each be part of a different rolling bearing. In one possible embodiment, there is a fixed ring which is arranged around the optical axis of the system and on the inner side of which an inner rolling bearing and on the outer side of which an outer rolling bearing are arranged, in which case the outer bearing shell of the outer rolling bearing and the inner bearing shell of
Bertelmann Dirk
Hopp Armin
Cariaso Alan
Sawhney Hargobind S.
Vorys, Sater, Seymour & Pease LLP
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