Wire rope tension grid improvements

These inventions improve the design of the current grid structure. The use, safety, and assembly of safe aerial platforms is likewise improved. The present invention is used to allow personnel safe access to high reach areas for mechanical tasks and maintenance operations, such as changing the position of theatrical lights, servicing air conditioning ducts, etc.

The wire rope tension grid has been in use for decades. It is usually installed in performing art centers, black box theaters, and in locations were it is difficult, impossible, or impractical to get a ladder or man lift in an area for maintenance. Through both the use and construction of many wire rope tension grid systems, InterAmerica Stage, Inc. has made various improvements to the structures. Currently we will be releasing a new line of improved wire rope tension grids. These grids will feature both the improvements that have been made over time by our firm and new improvements that have been developed and tested by our engineering staff.

Safety is one of the major reasons the wire rope tension grid is used. It minimizes the risk of falling while performing high reach operations using ladders or lifts. The other major benefit to the wire rope tension grid is that light can pass through without casting shadows on surfaces below it. This is particularly useful in the entertainment industry, where lighting of props, the focus of sound, and special effects placement are of the utmost importance in a performance.

Modularity: A wire rope tension grid is installed as a modular item, able to be removed for service and transported easily for erection. The connections to the modular attachments have been improved. Through-bolts connect hanger points to the grid. This provides a hard connection as opposed to a floating clamped connection. This is a further improvement over the pieces in the past that are non-modular, being welded to their respective support hangers.

Reducing the lateral stress on the wire rope within the wire rope tension grid was a major priority. Rolled edges and chamfered through holes have aided in this regard. Even the position of the hole itself has been reconsidered, and positioned accordingly. The cable is supported over the frame support tube increasing the area of impact and lessening the stress at any particular point in the cable. This allows for a horizontal load to be applied to the wire rope.

Structural strength of the frame has likewise been improved by adding support tabs that do not interfere with the location of the wire rope. These help distribute the vertical and torsion loads that are exerted on the frame while it is in use.

The bottom portion of the hanger connections were further improved, providing streamlined outer perimeter and corner connections for safe handling and aesthetics.

The top of the hanger mounting plates are sized to allow for a flush walking surface.

A lighting pipe outrigger system has been developed applying lighting fixtures or light bars outboard from principal wire rope tension grid suspension points.

Originally, a spacer on the wire rope was used to assist in the swaging of a copper stop sleeve on the wire. With the use of a new purpose built hydraulic swaging tool this is no longer necessary.

Through bolts within the frame allow for a rigid connection to adjacent wire tension grid panels. This helps to prevent the frame from bowing under stresses applied by taut wire rope.

In an instance where a wire rope tension grid system is required to have the wire rope non-perpendicular and non-parallel to the frame, a new way of distributing the wires had to be realized. A wire rope turn pin was added to the frame so that the wire rope can be weaved in the same way that the regular rectangular tension grids. The wire rope turn pin decreases the stress on the cable. Elliptical slots on frame for the cables further lessen pinch points.

FIG. 1 is a top view of one embodiment of a wire rope tension grid according to the present invention.

FIG. 2 is a front view of the wire rope tension grid of FIG. 1 .

FIG. 3 is a side view of the wire rope tension grid of FIG. 1 .

FIG. 4 is a top view of the wire rope tension grid; displays thru holes for mounting brackets, a lack of spacers at the termination points of the wire rope, and new support bar locations.

FIG. 5 is a side view of the wire rope tension grid; displays lowered cable thru holes for cable support, and thru bolt holes for mounting adjacent panels.

FIG. 6 is a top view of wire rope tension grid where wire rope is not perpendicular and parallel to the frame, displays wire rope turn pin.

FIG. 7 is a cross section of the frame with a wire rope turn pin.

FIG. 8 is a side view of a lighting pipe system. Displays the bracket that connects it to the hanger pipe.

FIG. 9 is a front view of the lighting pipe system of FIG. 8 .

FIGS. 10 and 11 illustrate a hanger assembly for connecting frames within grid system.

FIGS. 12 and 13 illustrate a hanger assembly for connecting frames at the edge of the grid system.

FIGS. 1-3 display a complete wire rope tension grid panel 10 . These wire rope tension grid panels 10 are constructed of mild steel tubing 12 and mild steel angle 14 . The dimensions of the said steel vary per application, but are most often constructed of 3/16″ thick 1.5″ times 1.5″ mild steel tubing 12 with a piece of mild steel angle 14 measuring 1.5″ times 1.75″

Holes 16 are predrilled into the mild steel angle 14 at increments of 2″ center. See FIG. 2 . These holes 16 are 5/32″ in diameter. Holes 18 , 20 are also predrilled into specific points on the mild steel tubing 12 for modular through-holes 18 and for hanger plate bolts ( 20 ). See FIGS. 4 and 5 . The through-holes 18 are used by bolts 22 with nuts 24 and spacers 26 to join and maintain the spacing of two adjacent wire rope tension grid panels 10 .

The mild steel angle 14 is welded onto the mild steel tubing 12 making the basic frame structure 28 . This basic frame structure 28 is reinforced by supports 30 welded above the locations of the through-holes 18 used for modular attachments. FIGS. 4 and 5 display these supports 30 as hidden lines.

FIGS. 6 and 7 display the use of the wire rope turn pin 32 . If the design calls for the use of this device then a hole will be drilled into the mild steel angle 14 and mild steel tubing 12 . The wire rope turn pin will then be inserted into the frame and will be plug welded from the top side of the angle.

Basic frame structure 28 is often powder coated or painted, often flat black, so that is not visually intrusive to the general public.

The wire rope 36 is then weaved into the frame by hand. The ends 38 of the wire rope 36 are inserted into the 5/32″ holes. A copper stop sleeve 40 is slid over the ends of the cable. A modified torque wrench is used to apply an accurate amount of tension within the wire rope 36 as the copper stop sleeve 40 is swaged onto the wire rope 36 . This is done on both sides of the wire rope 36 resulting in an evenly distributed amount of tension along the entire wire rope tension grid panel 10 .

The hanger assembly 50 is comprised of mild steel tubing 52 , often 1.5″ schedule 40 . The upper hanger plate 54 is welded onto the mild steel tubing 52 . Holes 56 are drilled in locations that correspond to the predrilled holes 20 in the frame's mild steel tubing 12 . The upper portion of the entire hanger assembly 50 varies per application and structure. Please see FIGS. 10 and 11 .

The lower portion 58 of the hanger plate assembly 50 is a steel plate that is drilled to correspond to the bolt holes 20 for the frame and the upper hanger plate 54 of the hanger assembly 50 . These parts are often painted or powder coated, often flat black, so that is not visually intrusive to the general public and so that it matches the frame.

A side version of a hanger assembly 50 ′ is illustrated in FIGS. 12 and 13 . The hanger assembly 50 ′ has mild steel tubing 52 ′ and. The upper hanger plate 54 ′ is welded onto the mild steel tubing 52 ′. Holes 56 ′ are drilled in locations that correspond to the predrilled holes 20 in the frame's mild steel tubing 12 . A lower portion 58 ′ of the hanger plate assembly 50 ′ is a steel plate that is drilled to correspond to the bolt holes 20 for the frame and the upper hanger plate 54 ′ of the hanger assembly 50 ′.

The entire assembly is erected on site and is bolted together using grade 5, ½″ times 13″ Carbon Zinc Plated Hex Head Bolt 60 , with a ½ Carbon Zinc Plated Nylok nut 62 , and flat ½ washers 64 .

FIGS. 8 and 9 display the outrigger lighting pipe system 70 , it is comprised of at least two pipe clamps 72 with screws 74 used to adjust the location of the system, a flat piece of mild steel 76 measuring the width of the pipe clamps 72 , a support beam 78 of mild steel, and an outrigger pipe 80 for hanging electrical equipment such as lights and speakers.

The pipe clamps 72 are measured out to fit the support hangers. Likewise, the outrigger pipe 80 is sized to fit common lighting fixtures with ease.

All of the parts of the wire rope tension grid system are design for modular installation, easy and safe use, and simple maintenance.