EP0152243B1

EP0152243B1 - Control pole for luminaires

Info

Publication number: EP0152243B1
Application number: EP85300691A
Authority: EP
Inventors: Joseph Thornley
Original assignee: Rank Organization Ltd
Current assignee: Rank Organization Ltd
Priority date: 1984-02-03
Filing date: 1985-02-01
Publication date: 1987-11-25
Also published as: GB8402971D0; EP0152243A3; DE3561081D1; EP0152243A2

Description

This invention relates to the pole operation of luminaires, i.e. light fittings which are usually mounted at a high level for providing illumination of a scene, typically in a television or film studio. Such light fittings include floodlights and various kinds of spotlight, and are often provided with so-called barn doors for modifying the beam pattern.
As a luminaire is often mounted at high level, sometimes a very high level, so called remote control poles have been produced to enable remote adjustment of the lumlnaire, i.e. from the floor or ground, in respect of pan (rotation), tilt, and focus, on/off switching and intensity selection, and also barn door movement.
One known remote control pole disclosed in GB-A-981 625, has a pole end fitting in the form of a hook which can be engaged with a eye on a fitting which attaches to the drive shaft to the luminaire. Another known pole has a pole end fitting in the form of a bayonet cup which engages a spigot and crossbar on the luminaire. A third known pole has a hooked end fitting on the pole which can be engaged with a crossbar spanning a bell-shaped fitting which attaches to the luminaire drive shaft.
US-A-2 773 975 discloses a lighting apparatus, e.g. a tubular lighting fixture, which is supported at an elevated level by cables attached to a winch driven by an electric motor. Part of a circuit for energising the motor is brought out to a socket on the apparatus. In order to complete the circuit to energise the motor, a control rod long enough to extend from the elevated apparatus to an operator standing on the floor is used. The rod includes at one end a plug which is pushed into the elevated socket, and a switch at the lower end for controlling the motor. A guide is provided around the socket to help guide the plug into the socket. The end of the rod with the plug may be flexible.
It is difficult to engage an end of a long control rod or pole with a device on a lighting apparatus high above floor level. In particular it is difficult to engage a hook with a small crossbar or eye on a luminaire at long range. The luminaire is often set swinging on its mounting and is difficult to focus and set. Similarly, when the conventional hooked pole is disengaged after luminaire adjustment, the act of disengagement often disturbs the luminaire.
According to one aspect of the present invention, there is provided a remote control pole for a luminaire comprising a pole and an end fitting for engaging a corresponding fitting on a luminaire, characterised in that the end fitting includes means selectively actuable to provide magnetic engagement with the fitting on the luminaire.
According to another aspect of the invention, there is provided a pole according to said one aspect in combination with a tuminaire comprising a fitting of magnetic material for magnetic engagement with the end fitting of the pole operator.
According to still another aspect of the invention, there is provided a method of operating the combination of said another aspect, wherein the pole end fitting is demagnetised prior to disengagement with the luminaire fitting.
The pole end and luminaire fittings are preferably male and female fittings which are correspondingly cone shaped. The end fitting on the pole preferably comprises an electromagnet. The electromagnet is switched on as the pole end fitting approaches the luminaire fitting, and thereby they become self engaging without for example the problem of trying to engage a hook with a small crossbar at long range. The act of switching off the electromagnet readily enables disengagement without disturbance. The same procedure can be equally carried out using a permanent magnet and associated buck coil for demagnetisation in place of the electromagnet.
In the accompanying drawings:

Figure 1 is a diagrammatic axial cross section through a remote control pole, and
Figure 2 shows a matching luminaire fitment.

The pole shown in Figure 1 comprises a pole 10 having a head, generally referenced 12, tiltable relative to the main portion of the pole on a spring support 14.
The pole head 12 comprises a hollow inner part 16, generally of cylindrical form, about which can rotate an outer part 18, also generally of cylindrical form. The references 20 denote bush bearings providing the rotary mounting for the outer part 18 of the head. This outer part 18 is integrally formed at its outer (upper) end as a conical cup-shaped female fitting 22 of magnetic material, associated with a coil 24. This cup/ coil combination 22, 24 constitutes an electromagnet.
Power for the magnet is supplied from a power line 26 via brushes and slip rings 28, and it can be seen that the pole 10 is hollow to accommodate not only the power line but also a flexible mechanical drive, eg. a sheathed cable 29 by means of which the cone drive 22 can be driven in rotation by a remote motor, and a tensioning wire 30 enabling the head 12 to be tilted to a required angle by pulling on the wire at the base of the pole.
It may be practicable and advantageous to provide a motor drive unit within the pole, either mains or the base of the pole. A single such motor drive unit could be operable to power all mechanical movements associated with adjustment of the luminaire, as compared to the three luminaire motors which are conventionally employed.
In use, the pole is approached to the luminaire and the magnetic cone drive is switched on. The cone drive fitting 22 is thus substantially self engaging to a matching cone shaped male fitting 40 attached to the drive shaft 42 to the luminaire (see Figure 2). When engagement has been effected, pan, tilt and focus adjustment may be carried out through the conventionally provided gear mechanism in the luminaire or alternatively, when a motor drive unit is provided on the hollow pole, by selective operation of push buttons at the base of the pole. Remote switching and intensity selection can also be carried out, whilst the barn door flaps at the front of the luminaire can be moved by utilising the magnetic attractive force produced by the switched on cone drive fitting 22 when it is approached towards said flaps. This method of operation only requires that the complementary cone-shaped fitting 40 on the luminaire should be of magnetically susceptible material, and likewise the barn doors, as would in any event normally be the case for such components or otherwise may have ferrous tabs applied.
Prior to disengaging the cone drive fitting 22 from the luminaire (or moving it away from the barn doors), the magnetic fitting is switched off or is demagnetised, thereby to enable ready detachment without disturbance of the adjusted luminaire (or barn doors).
As also shown in Figure 2, the luminaire fitting 40 is also provided with a crossbar 44 enabling alternative operation and adjustment of the luminaire by a conventional hooked pole operator.
Attention is also drawn to the tiltable head 12, which is conveniently about 30 cm long and by means of the tensioning wire 30 can be bent over to enable the drive to be effected with the pole at an angle to the vertical. This is important because more often than not the floor or ground directly beneath a luminaire is obstructed. The electrical and mechanical connection lines within the hollow pole have minimal effect on such tilting head movement and are minimally affected by such movement.
Finally, it will be appreciated that the embodiment described with reference to the drawings is by way of example only and may be modified in various ways within the scope of the invention defined by the appended claims.

Claims

1. A remote control pole for a luminaire comprising a pole (10) and an end fitting (12) for engaging a corresponding fitting (40) on a luminaire, characterised in that the end fitting includes means (22, 24) selectively actuable to provide magnetic engagement with the fitting on the luminaire.

2. A pole according to claim 1, wherein the end fitting (12) comprises magnetisable material (22) and means (24) selectively actuable to magnetise the material.

3. A pole according to claim 1, wherein the end fitting comprises magnetised material and means selectively actuable to demagnetise the material.

4. A pole according to claim 2 or 3, wherein the selectively actuable means comprises a coil (24) and means for selectively electrically energising the coil.

5. A pole according to any preceeding claim, wherein the end fitting is rotatable relative to the pole and further comprising drive means for rotating the end fitting relative to the pole.

6. A pole according to claim 5, wherein the drive means includes a sheathed cable (29) extending along the pole for mechanically rotating the end fitting.

7. A pole according to claim 5 or 6, when appended to claim 4 wherein the end fitting includes brushes and slip rings via which the coil is energised.

8. A pole according to any preceeding claim wherein the end fitting is tiltable relative to the pole.

9. A pole according to claim 8 wherein the end fitting is coupled by a spring (14) to the pole to allow the end fitting to tilt.

10. A pole according to claim 8 or 9 comprising a tension wire (30) for tilting the end fitting.

11. A pole according to any preceeding claim wherein the pole is hollow.

12. A pole according to claim 11 when appended to any one of claims 4 to 10 wherein the hollow pole houses the mechanically and/or electrical connections to the end fitting.

13. A pole according to any preceeding claim wherein the end fitting is of conical shape for mechanically engaging a complementarily shaped fitting on the luminaire.

14. A combination of remote control pole according to any one of claims 1 to 12 and a luminaire, wherein the luminaire comprises a fitting (14) of magnetic material for magnetic engagement with the end fitting of the remote control pole.

15. A combination according to claim 14, wherein the end fitting of the pole and the fitting of the luminaire are of complementary conical shapes.

16. A combination according to claim 15, wherein the end fitting of the pole is of conical cup shape and the luminiare fitting is conical to fit within the cup shaped pole end fitting.

17. A combination according to claim 14, 15, or 16 wherein the luminaire fitting includes a cross piece for engagement by an alternative remote control pole having a hooked end fitting.

18. A method of operating the combination of claim 14, 15, 16 or 17, wherein the pole end fitting is demagnetised prior to disengagement with the luminaire fitting.