The present invention relates to a hoisting device as defined in the preamble of claim 1.
Practically all theatres and other stages are equipped with such a hoisting device which usually comprises a large number of hoisting elements, simply referred to as battens, for the purpose of receiving scenery backdrops and other stage fixtures and optionally changing them during a performance. In addition to sets and other pieces of scenery, such stage fixtures also include in this context for instance spotlights, loudspeakers and other items of a more technical nature for the purpose of giving a performance added value.
The European patent application
Further
In theatres the vertical cables from which the stage fixture to be lifted is suspended are normally guided to a side of the stage on a so-called fly loft. Here the cables are brought together per group of lines and fastened to a vertically moving mechanism which is usually hand-operated. A number of such constructions in a row are normally referred to as a hoist wall. In an effort to create increasingly larger scale and spectacular productions, the number of fixtures and pieces of scenery that has to be changed during a performance is also increasing. The changes not infrequently have to take place here while the performance is progressing, so that a lot of time not usually will be available for this purpose. Increasing use is therefore being made of motorized operation of the hoist wall, whereby pieces of scenery can be raised and lowered in a short time. The speed at which this has to take place, and in particular the accelerations and decelerations thereby exerted in the lifting device, results in exceptionally great loads, particularly on the hoisting element which carries the stage fixture but which is not usually designed to withstand such forces.
The present invention has for its object, among others, to provide a hoisting device of the type stated in the preamble with a hoisting element which, while retaining its functionality, is able to withstand such an increased dynamic load resulting from a motorized driving.
In order to achieve the desired objective a hoisting device of the type stated in the preamble has the feature according to the invention that the hoisting element comprises a profile assembly of at least two elongate profiles which are substantially parallel to each other and which are mutually connected by at least one rigid intermediate body, wherein a first of the two profiles is coupled to the group of lines and a second of the two profiles is adapted to receive the at least one stage fixture thereon, and that the profiles are adapted on their outer end for coupling to a corresponding profile of a further profile assembly. By thus making use of an assembly of at least two profiles which are mutually coupled, the requirements the hoisting element must meet can be extended over the individual profiles. The first profile is herein adapted to the desired dynamic load which the hoisting element has to be able to withstand, while the second profile fulfills the hanging function and is adapted to enable easy coupling of pieces of scenery and other stage fixtures. Because the profiles are adapted on their outer end for coupling to a corresponding profile of a further profile assembly, it is possible to extend the hoisting element to any desired length by making use of one or more standard length dimensions.
In a preferred embodiment the hoisting device according to the invention is characterized in that the first profile has a substantially rectangular cross-section and the second profile a substantially round cross-section. The second profile with a round cross-section is herein adapted to generally applied fastening hooks and clips with which stage fixtures such as spotlights and loudspeakers are usually equipped and which grip round the hoisting element. The existing functionality of a conventional hoisting element is thus preserved. Conversely, the first profile has a rectangular cross-section in order to provide a greater bending strength and is thereby geared to withstand high dynamic loads during rapid deceleration and acceleration of the whole.
In a particular embodiment the hoisting device according to the invention has the feature that the at least one intermediate body comprises a number of separate intermediate members. By thus making use of separate rods instead of a continuous connection, an exceptionally light unit is achieved while retaining strength and which also has advantages in respect of weight-saving as well as from an aesthetic viewpoint.
In a further preferred embodiment the hoisting device according to the invention is characterized in that the first profile comprises on a side remote from the second profile a guide slot for receiving displaceably therein at least one fastening member for a hoisting line of the group of lines. By thus making use of a guide slot for receiving therein the fastening member of a line, the hoisting element can be manufactured and applied in a standard embodiment without having to take into account the specific positions and numbers of the lines in an actual theatre arrangement. The fastening members of the lines are placed easily in the slot and then guided to the desired position.
Backdrops are not infrequently tied releasably or otherwise tied fixedly to the hoisting element, which requires much manual work. So as to avoid this a further preferred embodiment of the hoisting device according to the invention has the feature that the second profile comprises on a side remote from the first profile a guide slot for receiving displaceably therein at least one fastening member of a backdrop.
Conventional curtain runners or other guides are for instance used here as fastening members on the backdrop so that as a result this backdrop can travel or slide as a curtain in the slot of the second profile.
For an easy mounting a further embodiment of the hoisting device according to the invention is characterized in that both profiles of the assembly are provided on sides directed toward each other with a recess in which an outer end of an intermediate body is received and fixed. Separate intermediate members can thus be placed in the profiles at the desired positions and fixed there. For fixing purposes use can for instance be made of a bayonet fitting or threaded connection so that welding work can be dispensed with and the whole unit can optionally be disassembled again. A further preferred embodiment of the hoisting device according to the invention herein has the feature that the recess in at least one of the two profiles comprises a longitudinal slot. A close-fitting nut can for instance be placed in such a slot so as to be connected at the intended location to an outer thread provided for this purpose on the outer end of the intermediate body. The intermediate body can thus be screwed fixedly into the profile at the desired location. The inner walls of the slot avoid co-rotation of the nut. By applying oppositely rotating threaded connections in the two profiles a simultaneous connection can thus be made to the two profiles.
The invention also relates to a hoisting element for use in the hoisting device according to the invention and will now be further elucidated with reference to an embodiment and an associated drawing, in which:
The figure is otherwise schematic and not drawn to scale. For the sake of clarity some dimensions in particular are exaggerated to a greater or lesser extent. Corresponding parts are designated as far as possible in the figure with the same reference numeral.
According to the invention the hoisting element 10 comprises a profile assembly of at least two elongate and substantially parallel profiles 11, 12 mutually connected by at least one rigid intermediate body 13. A first of the two profiles 11 herein has a substantially rectangular cross-section and is hereby designed to be able to withstand a dynamic load exerted thereon during rapid lowering and raising of the hoisting element. Conversely, a second of the two profiles 12 has a substantially round cross-section so as to fit standard couplings for spotlights and loudspeakers which usually grip round the hoisting element with a round hook or clip.
The first profile 11 is provided on its side remote from the second profile 12 with a guide slot 14 for receiving displaceably therein a number of fastening members 15. These fastening members 15 are pushed in guide slot 14 to the desired position and there coupled to a line 15 of the group of lines. If desired, the fastening members are fixed in this position.
The second profile 12 is also equipped with a guide slot 16 on its side remote from the first profile 11. Fastening members, such as for instance curtain runners, provided for this purpose on a backdrop can be received displaceably in this slot 16, so that a piece of scenery provided therewith can slide like a curtain in the hoisting element.
In this embodiment the two profiles are provided in the sides directed toward each other with a recess for receiving therein an outer end of an intermediate body 13 which is fixed therein for the purpose of the desired mutual connection of the two profiles 11, 12. In this embodiment the recess is embodied in both profiles 11, 12 as a continuous guide slot 17, 18. Herein slide nuts which are guided to the desired locations, where the intermediate bodies are screwed fixedly therein. The intermediate bodies are provided for this purpose on their outer end with a mating outer thread which takes an oppositely rotating form on either side. The threaded ends eventually clamp against a bottom of slot 17, 18 and are thus fixed in this position.
In practice a hoisting element can have a length in the order of 15-25 metres, depending on the actual stage width in the theatre or the width of another stage. Such a span is realized according to the invention by mutually coupling to the desired length a number of profile assemblies of one or more standard lengths. To this end the hoisting elements according to the invention are adapted on their outer end to enable such a coupling. In this embodiment the first profile 11 takes a hollow form in order to receive close-fittingly therein a connecting piece (not shown) of complementary form. This connecting piece protrudes as a result into both the hoisting elements for connecting and is secured therein. Instead of separate connecting pieces, use can also be made of hoisting elements which are widened on one of the two ends so as to receive close-fittingly therein an opposite end of a further hoisting element.
Although the invention has been further elucidated above with reference to only a single embodiment, it will be apparent that the invention is by no means limited thereto. On the contrary, many other variations and embodiments are possible for a skilled person without him being required to depart from the scope of the invention as defined by the apendent claims.
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.