14
LIFTS HOISTS AND ROOFS

When trusses were first used to solve the problem of luminaire support they were ground supported. When trusses began to be tied to the building's structure, the process, called rigging (borrowed from the circus and construction), came with its own set of considerations. First, many of the buildings did not have primary and secondary beams with adequate weight-bearing margins to hold the added weight. Second, the cost of hiring riggers was prohibitive. As the lighting systems and production grew in complexity in later years, it became necessary to use only qualified rigging specialists. This meant that the tour had to restrict itself, in some cases, to larger facilities such as basketball and hockey arenas.

But, the market for artists playing in smaller settings was still thriving. How could their shows be expanded but avoid rigging? The logical solution was improved ground support. Devices used in the construction trades could be adapted for touring use. Units were already on the market that allowed workers to change light bulbs and mount materials overhead in buildings. Since those early days of borrowing, structures have been devised by truss manufacturers to more safely lift bigger loads.

This chapter provides a summary of some of the types of lifts adapted for concert use and some examples of the finished products, including trusses and complete portable roof structures. Not all manufacturers are represented here, but we have tried to present an example of every generic type of lift, hoist, and roof, paying special attention to the ones that have received the most use through the years. These items represent savings of thousands of hours in labor. They often make the difference between performing with the lighting available or not taking the performing into the venue which limits bookings to theatres with existing structures. These devices are key to bringing theatre, dance, opera, and other entertainment to portions of the population that do not have equipped theatres in their communities and for opening up some exciting possibilities in found spaces.

AIR AND CABLE CRANK-UP LIFTS

We have moved on from the first generation of lifts— the Genie Tower and the Vermette Lift. These were lifts pulled right off construction sites. One lift from that era is still used, the Genie Super Tower.

Genie Super Tower

The Genie Super Tower operates using a 3/8-inch wire rope over a series of pulleys and offers the unique advantage of having a safety braking system approved by the Occupational Safety and Health Administration (OSHA). Another advantage is that the columns nest inside one another and are pulled out as you crank the forks up (Figure 14.1). The telescoping sections allow it to be used at less than the maximum extension. Two models are available—18- and 24-foot versions, each with a load capacity of 300 pounds. These units have two types of base configurations, both with excellent leveling jacks. It must be noted that Genie Industries (now owned by Terex Corporation) was one of the first outside companies to take a real interest in concert touring needs.

Eventer Stage Lift

Modeled on the Genie Super Tower, Sumner's Eventer Stage Lift (Figure 14.2) has updated 20- and 25-foot versions of the crank-up lift. Designed to fit compactly onto a truck tailgate or through a standard-height door, their lifting capacities are 640 and 800 pounds, respectively. It comes with wide outboard stabilizing legs that have end-mounted cranks for leveling. Note that the load-carrying capacity is double or more than that of the Genie Super Tower.

Air Deck

The Air Deck is a compressed-air-operated lift that is an adaptation of the old Genie Tower. Essentially, it ties together three air columns with a basket on top to create a lift for a person (Figure 14.3). If the load is not centered over the columns, the air seal is compromised and air leaks out, thereby preventing the lift from going higher or, if extended, it may come down slowly. Must not used in lifting or supporting trusses, the Air Deck is very popular as a focusing platform and sometimes as a follow spot platform. It has operating heights of 24 and 36 feet. The unit weighs in at 351 pounds and has a traveling minimum height of 7 feet, 5 inches. It is marketed by Upright Scaffolding, Inc.

RAM LIFTS

Several oil-operated ram lifts were used in the early days and may still be used in other countries, but in the United States they are no longer popular. Although some models can go very high (55 feet or more), the weight and size of these lifts have usually prohibited their use for touring. Load capacities of 500 to 1600 pounds can definitely be an advantage, but they have the same disadvantages as a Genie Tower: If the load is not directly over the column, the seals are broken and the unit could leak oil ors lip.

SCISSOR LIFTS

Oil and fluid systems have given way to scissor-type units. They have the advantage of stability, reach, drivability, and battery operation. There are many lift manufacturers due to the large construction

market. Figure 14.4 lists quite a few of these manufacturers, but for concerts the leaders seem to be Genie, Up Right, and Skyjack. Virtually all of these companies also make boom-type units, but they are not normally used for tours, although I have been in arenas where large units have been utilized to take riggers to high steel or other attachment points so they do not have to walk the steel. It is an obviously better and safe way to work.

Many theatres also have smaller units that they can use on their stages, but be sure to check with the building engineer or architect as to the weight loading of your stage floor, especially if there is a basement below.

A conventional scissor lift generally has a platform height of from 20 to 38 feet and a load capacity between 500 and 1200 pounds (Figure 14.5). More compact units extend to 21 and 25 feet but with reduced load capacities of 550 to 600 pounds. On the other end of the scale are units that have a working platform at 50 feet, are drivable over rough terrain, and hold 2400 pounds.

At times, these larger units are employed as front follow spot platforms because they can be moved into place quickly, they require no preconstruction time or safety wires, and the working height (beam angle of the spots) can be set by the designer onsite.

TRUSS TOWER LIFTS

Because of the unique problems associated with touring, several truss companies have developed their own lifts. Most market their towers as support for standalone speaker clusters or support for trusses or portable roof systems. The units discussed below represent only a few of the companies because there is a great duplication of systems and ideas. It should be noted that the towers manufactured for vertical use (i.e., legs) are generally different than a truss span or horizontal unit. Check with the manufacturer and do not mix the two.

Thomas Tower

James Thomas Engineering offers towers with either manual cable cranks or chain motor hoists to raise the trusses or speakers; the hoists ride up with the truss rather than being secured at the base. The lifting capacity of can be up to 4 tons. Towers can be built out of Thomas' 15 × 15-inch and 20 × 20.5-inch trusses that extend to 40 feet. The smaller 12 × 12-inch tower can be raised to 33 feet with a 2-ton load. If the towers are used to raise a truss, they are erected after the truss is assembled (Figure 14.6) and are placed inside the box of trusses (Figure 14.7). Note that in the figure six towers are

lifting the total grid. The motors are not synchronous, but they travel at a close enough speed to keep the grid reasonably level. Control units allow for a single motor or any combination of motors to work together. There is an optional base with outriggers that allows a tower to stand alone (Figure 14.8). The photograph shows the base detail with a Lode Star motor attached. The light frame holds 36 PAR-64 luminaires. Leveling and bracing are critical to the stability of any ground-supported truss system.

Versa Tower

The Versa tower is a self-climbing version that uses a motorized cable winch and can be up to 40 feet tall (Figure 14.9). It is supported by six legs that extend out from 6 to 7 feet in each direction. It has a 40-ton lifting capacity, which makes it ideal for full lighting grids or outdoor roofs. It is made by All Access, Inc.

Prolyte Products

Prolyte, a Netherlands-based company, has provided for either hand winch crank-up or motorized hoist

power. The hoist travels with the truss rather than remaining in the tower base. The base is a four-leg outrigger assembly. Several different truss sizes and heights are available. One interesting thing is that they publish a free book called the Prolyte Black Book (see Chapter 13), which covers safe working practices, basic truss knowledge, and the latest developments in regulations and standardization. There are many great companies who manufacture both trusses and towers.

HOISTS AND RIGGING

Rigging trusses or portable roofs can be accomplished in only a limited number of ways. The devices made for this purpose are very specialized. Some methods of rigging have been developed by

individual companies that have not gained wide acceptance. For large systems, such as in arenas or large convention centers, the circus approach to rigging is generally employed. By securing cables to the ceiling support beams (often referred to as the high steel) of the building, a truss or grid can be lifted and temporally suspended.

CHAIN HOISTS

CM Lode Star

Probably the most widely used hoists are Lode Star (Figure 14.10) motorized chain climbers, which were electric chain pulleys that originally had to be modified to operate in an inverted mode. The original motors had a gravity switch that had to be field modified. Since then, Columbus McKinnon (CM) learned what the concert market was doing with their motors and developed a new switch that would work in either condition with no liability, no matter how the motor was used, inverted or upright. It should go without saying that any modification

should only be done by a factory-authorized agent. The company is very aware of the touring applications and works closely with road technicians and rental houses to ensure proper maintenance. A certification program is also in effect through the manufacturer.

The load rating of the hoists in this series is from 1/4 ton up to 5 tons. The biggest drawback is that the chain can fall out of the collector bag, and there have been reports of slippage or brake release when the motor is disengaged. Many of these problems are due to poor operator handling and should not be interpreted in any way as being the fault of an unsafe product. The person using the device has a great responsibility to make sure the device is checked frequently and used properly at all times.

How the hoists are attached to the trusses is up to the user. The placement and size of each hoist are determined by the rigger. Figure 14.11 is a photograph of a flown lighting system with at least eight chain motors visible. Note the bridles on the two upstage points. In Figure 14.12, the motor to the left is bridled to the lighting truss to distribute the lifting load to two points instead of one. Note the “horse bucket” that catches the chain as the motor climbs up the suspended chain.

Stagemaker

Stagemaker hoists are made by R&M Materials Handling, Inc. Some hoists have built-in overload sensors and double brake systems, and they are available in sizes from 1/16 to 5 tons, with a 10:1 safety factor. The company also manufactures both fixed and variable speed hoists.

ChainMaster

Another contender in the field is ChainMaster (Figure 14.13), particularly its VarioLift series, which offers maximum precision and reproducibility in the positioning of chain hoists. The company claims a positioning accuracy of 0.2 millimeters using their integrated vector-controlled frequency converter, which is supplied by a high-impulse incremental encoder. Also available is the Jumbo Lift (Figure 14.14), which is designed to lift weights up to 6000 kilograms (13,200 lbs.) for heavy video cubes.

DIGITAL REMOTE CONTROL

All hoists commonly used in touring have their own multichannel control systems of from four to eight motors; however, some digital systems can control hoists in both directions and at different speeds at the same time. The Stage Master has been designed and tested to integrate with Nisco motion controllers Configuration E-Raynok (Figure 14.15). It has

a computer-based program that can accommodate 12 controllers and 96 hoists in a preprogrammed set of cues. Skjonberg Controls, Inc., is an independent manufacturer of controllers that has worked in touring since the 1980s. Four- and eight-channel controllers and a 40-channel design with a wired load cell capacity are available (Figure 14.16). Chain Master not only makes hoists but can also provide a console that controls hoist movement along all three axes, called the XYZ Stage Controller.

LOAD CELLS

The Ron Stage Master line not only offers multiple channel hoist controls but also features a wireless system to monitor weight overloads (Figure 14.17). This system is built by Eilgon in Israel. It includes a rather new safety device that is worth attention. A wireless device, called a load cell, can be attached between the hoist and a load point; it sends information via wireless signals to a laptop, which can have a computer-aided design (CAD) truss plan overlay that displays over- or underloads placed on points on the rig. No more human calculation mistakes—the device reads out the load in digital numbers. The systems can be set for 5:1 or 10:1 safety factors. The systems show real-time loads on a computer load map and can handle up to 256 load cells. As stated earlier, Skjonberg Controls makes a similar unit, but it is a wired system of up to 40 channels. Another company is Kinesys, which also uses a wired system.

Figure 14.18 provides a list of hoists and accessories.

SAFETY FIRST

The ground lift and hoist methods discussed here are representative of what is now in use in the field. None of these items is foolproof. Accidents occur mostly because we sometimes use these devices for purposes other than what they were designed for by the manufacturer. Safety should be the watchword for anyone using these methods. Consult the manufacturers. Most of them have become interested in the concert use of their products and can offer suggestions on the proper procedures for these applications. They want to protect you and themselves from law suits. Always use a skilled rigger whenever hoists are involved to protect the building as well as the audience, the artists, and the production company. This is not an area where the manager can skimp.

ROOFS

Roofs are generally trusses designed for portable concert rigs combined with their towers or lifting devices or hoists; however, there are exceptions. Specialized trusses have been built for this specific purpose, including domed designs, such as the one by Prolyte shown in Figure 14.19. The purpose of this section, however, is more about discussing companies that may not be the actual manufacturers but instead provide the services of constructing roof systems, staging, and even grandstands, in addition to providing the crews to assemble and transport the equipment.

Brown United

One such company, Brown United takes a unique approach to roof support construction that involves a base of I-beams that are set under the stage with the 4- to 30-inch round steel columns that are sometimes as tall as 55 feet and raised via motors in the roof to give the most unobstructed view possible (Figure 14.20). Sometimes four additional poles are used to build outboard sound wings. Figure 14.21 shows a side view of lighting and speaker clusters all supported by four poles. I have worked with this system several times on the beach in Hawaii with the I-beam buried in the sand; people can hardly believe such a large roof is supported by these simple posts. The system also allows for one of the tallest freestanding roof structures at 80 × 100 feet (Figure 14.22). Wings can be attached at the sides for sound or projection screen placement using

additional poles. Naturally, the size of the columns and the number vary depending on the total roof structure desired. Each is engineered based on the purpose and the additional weight the roof must support.

Mountain Productions

Mountain Productions, a leader in staging and outdoor roofs for 27 years, is headquartered in Pennsylvania. They manage over 200 events a year and provide staging, grandstands, towers, scaffolding, trucking, and staff for a wide variety of events besides rock & roll concerts (Figure 14.23).

Traveling Stages

Several companies have designed stages that are affixed to a flatbed trailer body and can be hauled into position and set up quickly. While they may not be doing the next Rolling Stones tour, they are a vital part of touring for many up-and-coming bands and can be seen at many outdoor club-size tours. They are also very active in the county fair circuit. One such company is Stageline Group; Figure 14.24 shows one of their mobile stages as it is opening up. Figure 14.25 shows a portable stage in use with supporting sound wings and video screens.

For a list of roofing and staging companies, see Figure 14.26 .