Illumination – Light source and modifier – Adjustable or repositionable light source or light source...
Reexamination Certificate
1999-05-26
2001-05-01
Husar, Stephen (Department: 2875)
Illumination
Light source and modifier
Adjustable or repositionable light source or light source...
C362S285000, C362S368000, C362S371000, C362S419000
Reexamination Certificate
active
06224242
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a luminaire comprising:
a housing with means for accommodating an electric lamp therein;
a mounting bracket for fastening to a support;
a coupling which connects the housing adjustably to the mounting bracket.
Such a luminaire is known from U.S. Pat. No. 5,353,211. In the known luminaire, the coupling consists of a threaded bolt which is screwed into a threaded hole in the housing. Before the threaded bolt is completely tightened, the bolt forms a horizontal shaft about which the housing can be pivoted upwards or downwards so as to illuminate the desired field by means of the luminaire. Once the correct position of the housing has been found, the latter is fixed in that the bolt is tightened.
Luminaires are often used in locations where they are accessible with difficulty, often from one side only, for example from the rear. This is the case, for example, when a luminaire is used for lighting, for example, a sports ground and is mounted against a framework at the top of a mast or at the edge of a roof, for example the edge of the roof of a spectator stand. It may be necessary in that case to loose the coupling and rotate the housing in the case of maintenance of the luminaire, for example for cleaning a reflector in the luminaire or a transparent plate which closes off the housing, or for replacing a lamp.
In a luminaire of the known kind, the housing must be accurately realigned when the maintenance work has been completed so as to achieve the original adjustment again. This is time-consuming and requires craftsmanship. The necessity of a repeated alignment is accordingly a major disadvantage of the known luminaire.
The adjustment of the housing with respect to the mounting bracket, with the object of throwing the light beam formed by the luminaire in the desired direction, should not be confused with the positioning of an electric lamp in the housing of the luminaire so as to give this lamp the correct position relative to a reflector in the housing and to create a light beam of the desired shape, i.e. with the desired light distribution. The essence of the luminaire described in the cited U.S. Pat No. 5,353,211 indeed lies in this adjustment of the shape of the light beam.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a luminaire which is of a simple construction and which renders it possible to replicate a previously determined position of the housing with reference to the mounting bracket after a rotation of the housing.
According to the invention, the coupling comprises a first part which is fixedly connected to the housing and a second part located in or around and coupled to the first part and fastened to the mounting bracket,
the first and the second part being rotatable relative to one another, and
the coupling having a blocking device with an operational position from which it can be released, and with release positions,
which blocking device in its operational position locks the first and the second part in a previously defined mutual rotational position.
The luminaire is brought into position and fixed while the blocking device of the coupling is in its operational position. During alignment of the luminaire, the connection between the coupling and the mounting bracket is loosed, so that the second part is in an adjustment condition, and the housing is steplessly rotatable about the mounting bracket. To this end, for example, a sight may be fastened to the housing, or the lamp in the luminaire may be lit. As soon as the correct adjustment has been found, the housing is fixed in this position in that the loosed connection between the second part of the coupling and the mounting bracket is fixed.
When maintenance work is to be carried out on the luminaire now, for which purpose the housing is to be rotated together with the first part of the coupling relative to the mounting bracket in order to be accessible to the service engineer, the blocking device is loosed, so that the first part of the coupling becomes rotatable relative to the second part, and the blocking device is removed from its operational position as far as is desired. After the maintenance work has been completed, the housing is rotated back and the blocking device is brought into its operational position again so as to lock the first and the second part of the coupling against mutual rotation. The housing can thus be returned to its original operational orientation in a comparatively simple manner.
It is practical when the blocking device comprises a resilient blocking element and a seat which cooperates therewith in the operational position. A force is then required for removing the resilient blocking element from its seat. In an embodiment of the luminaire, this may be a force which is exerted for the purpose of rotating the first and the second part of the coupling relative to one another. To prevent inadvertent rotations, the force necessary for rotation is greater than a chosen minimum force, while less force is necessary for a subsequent further rotation. Upon turning back into the operational position, the resistance to rotation will increase appreciably after the operational position has been reached, and the fact that the operational position has been reached may also be audible by means of a click.
The resilient blocking element may be, for example, a shaped blade spring, for example with a V-shaped portion which may grip into a recess, for example V-shaped, as the seat. It is alternatively possible for this blocking element to comprise a ball which is under spring pressure. The housing will then quasi-automatically enter the same position as before, without a visual inspection being necessary.
In an alternative embodiment, the blocking member has a blocking element in the form of a pin under spring pressure, for example a pointed pin, which can enter a bore, for example a cylindrical bore, as the seat. The cylindrical bore may have a tapering entrance so as to be easily accessible. When the blocking element has been pulled from its seat against the spring pressure, the parts of the coupling can be mutually rotated. When the parts are rotated back, the blocking element will enter its seat again under spring pressure when the original position of these parts has been reached. This embodiment has the advantage that an inadvertent rotation, for example under the influence of strong wind, is prevented.
It is alternatively practical when the blocking element is a rigid body, for example a screw, which is introduced into a seat through rotation, for example a screw with a conical tip in a conical seat. This embodiment has the advantage of a high storm resistance and also of a high reliability, because material fatigue of a spring cannot play any role. A screw having a conical tip in a matching seat has the additional advantage of a very high positioning accuracy and a small play.
When this blocking device is to be returned from a release position into the operational position, said rigid blocking element may be given a slight compression force, so that a friction will obtain during the rotation of the parts of the coupling relative to one another, which friction will disappear the moment the blocking element has arrived opposite its seat. A conical entrance to this seat is favorable in this respect.
In a special embodiment, the luminaire has a first blocking device with a resilient blocking element which moves from the release position into the operational position under spring pressure, and a second blocking element which comprises a rigid blocking element. This embodiment has the advantage that after a rotation of the housing, which is then to be returned to its original position, said original position can be readily found back from the fact that the resilient blocking element springs into its seat, which is noticeable from an increased or very high resistance to rotation, depending on the design of this element and of the seat, and the luminaire is locked in this position through the action of a rigid blocking elemen
De Vries Gert-Jan B.
Giraud Christian
Van Duinen Niels
Faller F. Brice
Husar Stephen
U.S. Philips Corporation
Ward John Anthony
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