GB2417938A - Theatre drive system - Google Patents

Abstract

A counterweight drive system comprising, a support frame 11, a drive system comprising at least one hoist motor 12, at least one header pulley 14 and at least one return pulley 15, connection means 13 to connect said drive system to flat(s) or other item(s) to be raised and lowered, and control means to control the operation of said drive system. Preferably, the motor is a steel band motor and the frame is the conventional one used for a conventional counterweight system. The use of the steel band motor allows the normal counterweights to be done away with and allows the system to be retrofitted to replace existing weighted systems. A band clamp 13 is also provided. Preferably the header pulley has a central, multi-stranded pulley and a flat band pulley either side thereof (Fig 2B).

Description

24 1 7938

IMPROVED EQUIPMENT

Filed of the Invention The present invention related to counterweight systems. It is particularly applicable, but in no way limited, to methods and apparatus for providing counterweight drive systems associated with theatre scenery including flown scenery and equipment about the stage.

Background to the Invention

The majority of theatre venues in the UK and Europe use a variety of powered & manual winches or counterweight systems to move and position technical equipment and show specific scenery, masking etc for each separate staging event. In the United Kingdom these systems currently fall in a 'grey area' between two sets of safety legislation. For part of the operational day they are covered by the general UK working procedures, such as the 'Places of Work' directive and standard risk assessment procedures - 'Management of Health & Safety at work (1999), COSHH, Riddor (Reporting of Injuries, Diseases & Dangerous Occurrences Regulations), CDM, Machinery Directive, CEN Standards etc. However, for the 'show' part of the day, they are covered under a separate set of rules & regulations, usually governed by the relevant local authority as part of the public performance licence granting procedure, : .'.. which traditionally have been more 'flexible', due to local knowledge and understanding <.. . with authority inspectors. ..

Current policy changes, mainly resulting from incoming European reviews and :. compliances, are moving the entertainment industry and all associated equipment 6. 25 towards the more general, overall industrial legislation, such as Loler (Lifting Operations & Lifting Equipment Regs) rules & PUWER (Provision & use of Work Equipment Regs).

Trade bodies such as the ABTT, PLASA & the PSA are working to 'temper' the affects ., of these new working practices, but it has become clear that many of the long established methods of staging an event in a theatre or general venue will be changing in the next year or so. For example, the use of a 'tallescope' is under question due to several incidents in the recent past and without this very basic and traditional piece of access equipment, many Theatres & Venues will be under great pressure to install new rigging & safety systems & revising working practices.

Existing Counterweight systems break just about every safe working practice guideline in the 'MoHSaW' book. Current systems require loading of up to 500kg in each of up to 50 cradles. This load is made up of cast steel weights of between 7.5kg 15kg, which are usually stored at floor level. The technician has to kneel on the floor - usually metal - and twist through 180 with the weight in their hands, arms at full extension, then angle the weight to insert it into the cradle. This action may need to be carried out 500 times to fully load up a fairly regular sized show and in a big Number 1 tour house, that equates to 40,000 separate operations a year.

Even if this loading method was allowed to continue, or was mechanised by some kind of fork lift, the transfer of loads into the counterweight cradle would require such complicated guarding to prevent the weights falling to the stage level, it would make the whole working environment, as it currently exists, utterly impractical.

In summary, existing counterweight systems are labour intensive, require high maintenance and are slow to lead. This can mean long fit-ups and expensive overtime.

There are therefore serious shortcomings with the present systems and the cost to replace such a system with entirely new, winch-driven equipment is uneconomic. More importantly, some venues are just not built to accommodate them. Extensive building work would be needed and often there is physically just not enough room in the building itself to allow for this. It is therefore an object of the present invention to overcome or mitigate some or all of the above problems. ë - I.

Summarv of the Invention .. According to a first aspect of the present invention there is provided a 4.

counterweight drive system comprising: (i) a support frame; (ii) a drive system comprising at least one hoist motor, at least one header pulley and at least one return pulley; (iii) connection means adapted to connect said drive system to flat(s) or other item(s) to be raised or lowered, said connection means comprising a plurality of bands connected to at least one wire or rope by means of a clamping means; (iv) control means to control the operation of said drive system.

The use of a band motor provides a quiet, compact drive system that enables the counterweight drive system to be installed in place of existing manual counterweight systems.

Preferably said hoist motor comprises an electrically driven steel band motor and the connection means incorporates one or more steel bands.

Preferably the header pulley comprises a counter-rotating pulley assembly, having two outer pulleys, one positioned on each side of the pulley assembly and at least one central pulley, said two outer pulleys and said central pulley being adapted to rotate independently of each other. This counter-rotating pulley system further contributes to the compactness of the counterweight drive system.

In an alternative preferred embodiment the two outer pulleys are constrained to turn in unison.

Preferably the two outer pulleys are adapted to accommodate bands and the inner pulley is adapted to accommodate rope or wire, such that the outer pulleys having broad pulley surfaces adapted to accommodate steel bands and the central pulley has a series of channels on the pulley surface adapted to retain wires or ropes.

Preferably, alternatively, the header pulley comprises a pulley assembly, said header pulley assembly comprising a first pulley adapted to accommodate a plurality of bands and a second pulley adapted to accommodate rope or wire, the first and second pulleys being adapted to rotate independently of each other.

Preferably in operation, the band(s) from the motor pass over the header pulley abets and down to a steel band clamp, the routing of the bands and take off to a fly bar thus e . approximating to a conventional arrangement.

A. a. Preferably the counterweight drive system is adapted to be retrofitted into an existing theatre, wherein said support frame comprises an existing frame designed to accommodate counter-balance weights of a theatre counterweight flying system.

e e Brief Descrintion of the Drawings The invention will be further described, by way of example only, with reference to the accompanying drawings in which: Figure 1 illustrates a side elevational view of a counterweight drive system according to one embodiment of the present invention; Figures 2A and 2B, 3A and 3B illustrate front and side elevational views respectively of a header pulley as shown in Figure 1; Figure 4 illustrates a steel band damp clamping means; Figure 5 illustrates a return pulley arrangement; Figures 6 and 7 illustrate front and side elevations of a hoist motor arrangement according to a further embodiment of the present invention; Figure 8 illustrates a flying system according to a further embodiment of the present invention.

Any dimensions or radii shown in these figures are included by way of illustrative examples only. The invention is not to be considered limited by size in any way. The assembly will be sized and adapted by the person skilled in the art to be appropriate for each particular application.

Descrintion of the Preferred Embodiments Embodiments of the present invention are described below by way of example only. These examples represent the best ways of puking the invention into practice that are currently known to he applicant, although they are not the only ways in which this could be achieved.

Referring to Figure 1, this illustrates, in somewhat diagrammatic form, a counter-weight drive system 10 comprising a support frame 11 onto which is mounted a steel band motor 12 and a steel band clamp assembly 13. Also provided, and this may O be mounted separately to the support frame itself, is a header pulley 14. The location . of the header pulley will depend upon the space, arrangement, set up and requirements of each installation.

Also provided are two return pulleys 15A and 15B, mounted near or at the bottom of the support frame.

The inventiveness and success of the present invention comes from the realization that an electric motor, particularly a steel band motor, can be used to raise .e and lower fly bars and flats accurately and quickly and, more importantly, the counterweight framework of an existing counterweight system can be used in its entirety with virtually no modification other than removal of the weights. This possibility, which had not been considered before, has meant that a relatively inexpensive, and equally importantly speedy, retrofit can be achieved in theatres with existing counterweight systems. Not only can the adaptation be achieved quickly but there is minimum disruption and generally no building work to be done. This avoids closing a theatre for long periods in order to make such a changeover.

The present invention, codenamed DGS, can be retro-fitted to most counterweight flying systems and will run happily with a 500kg load at 1. 5m/second.

Costs are comparatively low, because the main elements of the original system are retained and a block bank of 5 hoists can be installed in under 24 hours. This rapid installation time is a direct result of re- using the support frame from an existing counterweight flying system and also re-using the fly bars, pulleys etc associated with it.

Tuming to the various components in the system, a steel band motor is preferred, although it is not the only type of motor which can be used. Steel band motors, as supplied for example by ASM Steuerungstechnik GmbH of Bad Wuennenburg, Germany, have a number of distinct advantages compared to other means of load carrying. The steel band is extremely robust and has especially good high-speed features.

The steel band hoist is equipped with an extremely strong high-grade steel band that has been developed especially for ASM. Its edges are rounded off in a special process in order to exclude the danger of injuries. Its gauge varies from 0.4 to 0.5mm and its width from 20 to 60mm depending on the application. The tensile strength of the material amounts to 1.650 N/mm2 for example, a 0.5 x 30mm steel band has a load-carrying capacity of up to 2.5t.

Other advantages include: ë

Very quick, noiseless, end smooth running Long life (recommended replacement period 10 years) and easy replacement of the band ....DTD: No elongation of the carrier Carrier free of lubricants (various colour coatings possible) ë Non-spinning carrier .e Reel winding - light and compact machines despite long hoisting heights The carrier is almost invisible with the appropriate adjustment Whilst the use of steel bands is preferred, other types of band can be used, such as those made of Kevlar (RTM). In essence, any strong, relatively thin band material can be used providing it will perform the necessary duty and is relatively silent and smooth running in operation. The invention is therefore intended to encompass within its scope any suitable band-like material either known or yet to be discovered.

It is normal to use two bands per motor as a safety measure, in case one band should snap or break. However, one band would be sufficient to perform the necessary duty.

A special header pulley assembly 20 has been developed, shown in more detail in Figures 2 and 3, which allows the two steel bands from the motor to travel in one direction whilst the wires attached to the fly bar may travel in the opposite direction.

The three distinct pulley regions 21, 22 and 23 are shown in Figures 2B and 3B.

Pulleys 21 and 22 have a surface broad enough to accommodate a steel band whilst pulley 23 has a series of channels adapted to retain wires or ropes. Corresponding numbering has been used in Figure 3.

This is a particularly compact arrangement and dispenses with both the need for a series of separate pulley wheels, with their attendant supports, and with the more common arrangement whereby the wire(s) are positioned outside of the steel bands.

This space-saving, compact arrangement is one of the features which makes it possible to re-use the existing counterweight support frames. In operation, the steel band(s) from the motor pass over the header pulley and down to the steel band clamp 13. The . . routing of the bands and take off to the fly bar then approximate to a conventional . arrangement, with the take off, or take offs, passing over the header pulley as shown in Figure 1.

In practice the two pulleys 21 and 22 adapted to accommodate the bands would be coupled or otherwise constrained to rotate in unison. This ensures that the band clamp remains horizontal at all times.

. A motor control system is required and this can be a manual system, with an bane..

operator starting and stopping the motor manually when the fly bar is in the desired position. Alternatively a microprocessor control unit can be used to provide a degree of automation. Such control systems are known per se.

The dimensions shown in Figure 2 are for illustrative purposes only and are not intended to be limiting in any way.

A typical band clamp, in this example a steel band clamp, 13 is illustrated in more detail in Figure 4. Similarly, a return pulley assembly 15A and 15B, is illustrated in Figure 5. The return pulleys generally rotate independently because the movement of each band is controlled by the motor 12 and rotation of the band portions 21 and 22 of the header pulley assembly.

An alternative embodiment is illustrated in Figures 6 and 7. This shows a band motor 112 driving a gearbox 117 attached to a pulley assembly 114 and a brake 118.

In this arrangement a separate pulley (not shown in this figure) is provided to accommodate the wire(s) between the band clamp and the fly bar. This arrangement avoids the cost of a counter-rotating pulley assembly and provides for a separate wire or rope carrying pulley that may counter rotate with respect to the band pulley as necessary.

Figure 7 illustrates a side view of the arrangement shown in Figure 6, with the assembly mounted on a mounting bracket 119. The compactness of this arrangement will be seen from these preceding figures, this compactness contributing to the retrofit possibilities.

Figure 8 illustrates, in highly diagrammatic form, a counterweight drive system 200 according to a further embodiment, showing how this invention can be used as a retrofit to replace an existing cable counterweight system. A bottom pulley assembly - 215 is screwed or bolted to the floor 230, with screws or bolts 231 and with the A. possibility to adjust the pulley assembly for alignment purposes. Two steel bands 232, 233 are arranged such that they are central to the cradle 239 in both directions, is 25 vertically and laterally. The steel bands are driven by a motor 212 via a header pulley system 214. The motors are held firmly in place on a framework formed from appropriate material such as U-profile or tubular steel 241, 242. In other respects this arrangement is similar to those described above. ë.e

Counterweight drive systems according to the present invention may be retro fitted to most counterweight flying systems and will run happily with a 500kg load at 1.5m/second. Costs are relatively low because the main elements of the original system are retained and a block bank of 5 hoists can be installed in under 24 hours.

In summary, this present invention provides a host of advantages not available with other systems. These include: Near silent operation less than 30dB at stage level Lease purchase costs can be lower than current monthly crew labour costs Reduce loads on building structure by<50% Reduces fit-up times - no loading sessions required Use all lines simultaneously - with minimal fly crew/operators Dramatic savings on installation/get-in crew costs Fits to your existing counterweight system - most manufacturers versions Rental scheme available, meaning the system doesn't appear in an asset register Minimise future H&S problems or claims for back injuries etc Clean, efficient and safe Can be installed in normal working time or overnight - no long-term closure of the venue Low cost entry-level models available High spec, high-speed options Full weight-load & motion monitoring options via on-board dams card No brakes required on base models - drive & control system can be BGV C1 certified 10:1 safety factor on all added components - far better than the current hauling line & fixings breaking load of 2,000kg on each band - with a 10-year guarantee ë..

: 100% operational cycle possible Low speeds - down to 1mm/second - as standard Speeds up to 1.5m/second achievable . Loads up to 750Kg on selected models : ' Wide range of control options, from simple up/down/e-stop to fully synchronized systems Low maintenance costs Doesn't cost more to run after 1 O:OOpm - or require regular breaks for food and water.

Claims (9)

1. Claims: 1. A counterweight drive system comprising: (i) a support frame;

   (ii) a drive system comprising at least one hoist motor, at least one header pulley and at least one return pulley; (iii) connection means adapted to connect said drive system to flat(s) or other item(s) to be raised or lowered, said connection means comprising a plurality of bands connected to at least one wire or rope by means of a clamping means; (iv) control means to control the operation of said drive system.
2. 2. A counterweight drive system as claimed in Claim 1 wherein said hoist motor comprises an electrically driven steel band motor and the connection means incorporates one or more steel bands.
3. 3. A counterweight drive system as claimed in any preceding claim wherein the header pulley comprises a counter-rotating pulley assembly, having two outer pulleys, one positioned on each side of the pulley assembly and at least one central pulley, said two outer pulleys and said central pulley being adapted to rotate independently of each other.
4. 4. A counterweight drive system as claimed in Claim 3 wherein the two outer pulleys are constrained to turn in unison.
5. 5. A counterweight drive system as claimed in Claim 3 or Claim 4 wherein the two outer pulleys are adapted to accommodate bands and the inner pulley is adapted to accommodate rope or wire, such that the outer pulleys having broad pulley surfaces adapted to accommodate steel bands and the central pulley has a series of channels on the pulley surface adapted to retain wires or ropes.
6. 6. A counterweight drive system as claimed in Claim 1 or Claim 2 wherein the header pulley comprises a pulley assembly, said header pulley assembly comprising a first pulley adapted to accommodate a plurality of bands and a second pulley adapted to accommodate rope or wire, the first and second pulleys being adapted to rotate independently of each other.
7. 7. A counterweight drive system as claimed in any preceding claim wherein, in operation, the band(s) from the motor pass over the header pulley and down to a steel band clamp, the routing of the bands and take off to a fly bar thus approximating to a conventional arrangement.
8. 8. A counterweight drive system adapted to be retrofitted into an existing theatre, wherein said support frame comprises an existing frame designed to accommodate counter-balance weights of a theatre counterweight flying system.
9. 9. A counterweight drive system substantially as herein described with reference to and as illustrated in any combination of the accompanying drawings. . . A. . - . . :e ë . ë e