Modular Tower

Abstract

A prefabricated modular tower structure in which the ends of each of the legs of one module are joined to the legs of an adjacent module by an integral angularly disposed connector tube adapted to receive two bolts.

Description

The invention relates generally to a modular tower structure and more particularly to a modular tower which utilizes at the ends of each leg angularly disposed tubes which are bolted together to fasten the several modules of the tower together.

With the ever increasing use of communication systems, lighting systems, scaffolds, etc., there is an established need for a lightweight tower structure which is strong, yet requires minimal storage and transportation volume and can be rapidly and sturdily erected. Presently there are two methods of assembling and erecting towers.

In one method, the tower is completely built in lengthwise sections of predetermined height in a prefabricating shop and then shipped to a tower erection site where the sections are assembled, one on top of another, until a desired tower height is obtained. Typical patents describing this type tower are: U.S. Pat. Nos. 2,267,638; 2,305,563; 2,462,429; 2,893,521; 3,360,288; 3,156,329; 3,365,853. The other method is to transport the tower in small basic components in unassembled condition then, at the job site, assemble the components into a tower. Typical patents describing this type are U.S. Pat. Nos. 2,014,784 and 2,060,436.

The particular form which the tower (or scaffold) takes is generally dictated by its intended use. For instance, towers which are adapted to carry heavy loads are generally constructed, in the field, from precut structural steel form. However, towers intended for supporting lighter loads may be prefabricated in modular units and these modules assembled at the site of the tower construction.

In modular construction, it is common practice to join two sections together by passing bolts, rivets or other similar fastening means through the tubular legs to join them together. The legs commonly overlap each other for a short distance. This type of joint is objectionable in that the holes for the bolt passage usually weaken the legs, particularly when they are placed in tension. Sometimes the fasteners are tightened to such an extent that the tubular leg is flattened. This is particularly true where the tubular leg has a relatively thin wall. Such deformation causes the leg to assume an oval or other cross section and this reduces, in at least one direction, the effective radius of the leg, thus reducing its strength in column action.

It is therefore an object of this invention to provide a novel modular structure which maintains the full working strength of its legs.

Another object is to provide a connector joint for a modular tower which avoids passing bolts or other fasteners through the tower legs in a radial direction.

Still another object is to provide a prefabricated modular tower, the connector joints of which are as sturdy as the legs to the modular sections.

A further object is to provide a modular tower connector joint which has a minimum amount of play.

A still further object is to provide a modular tower connector joint which is easy to assemble whereby the amount of assembly labor needed is diminished.

Another object is to provide a modular tower structure which may be assembled at the erection site by simply connecting the modules with bolts.

Another object is to provide a modular tower structure which, during assembly, has a self-aligning ability by reason of the unique connector joint.

Another object is to provide a modular tower structure in which the modules are easily transportable with minimum use of space.

Another object is to provide a modular tower structure which is economical to manufacture.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The above and other objects not specifically enumerated are efficiently attained by providing on the ends of each leg of the tower an angularly disposed connector tube through which a bolt or other similar fastening means is then passed and tightened. The connector tube is preferably welded on the end of the tower leg and so angularly disposed with respect to the leg of the adjacent module and its connector tube so that the bolt may be easily slipped through the cavity of both connector tubes.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description in which:

FIG. 1 is a broken front view of an erected modular tower illustrating the manner in which the connectors of the present invention operate.

FIG. 2 is a top view of FIG. 1.

FIG. 3 is a cross-sectional view of one connected joint through line 3--3 of FIG. 2.

FIG. 4 is an exploded cross-sectional view of a second embodiment of a joint.

Similar reference characters refer to similar parts throughout the several views of the drawing.

Referring now to FIG. 1, there is shown a prefabricated modular tower 10. Each section or module 12 may be of any desired length, usually 8 or 10 feet, so that handling and transporting of the module is made easier. The tower sets on a suitable base 14, usually a sound concrete footing of customary design. Its upper end supports a superstructure 16 which may be adapted to support a platform, an antenna system, or a light system or any other high device.

The tower may be supported by a plurality of standard guy wires (not shown) which may be attached, in any suitable manner, to the tower at various points and to a suitable anchoring means in the ground.

Each module 12 has a plurality of vertical legs 18 which may either be tubular or solid. The module shown in FIG. 1 has three legs in horizontal cross section through the tower which form an equilateral triangle (see FIG. 2.). It is also possible to use a greater number of legs, such as four, five, six, etc. with appropriate change in the cross-sectional configuration such as a rectangle, pentagon, hexagon, etc.

Legs 18 are maintained in a rigid, spaced relationship with respect to each other by a lattice work of truss chords 20 of conventional construction. Typically, truss chords 20 are formed into a plurality of W, X or Z shapes which are welded or otherwise attached to legs 18.

The ends of each leg 18 of each module 12 have a connector tube 22 secured thereto, usually by welding. The tube 22 of the upper module has the same angular relationship as the mating connector tube of the lower module (see FIGS. 3 & 4) whereby a bolt 24 may be simply passed therethrough to join the upper and lower modules together. A nut 26, with or without washers 28 and 30, is threaded on the bolt until the two connector tubes are tight.

Referring now to FIG. 3, the tubes 22 are shown with abutting end faces 32 angular to a horizontal plane.

FIG. 4 illustrates the situation where the connector tubes 22 have abutting end faces 34 which are in a horizontal plane. The connector tube end face of FIG. 3 is preferred because, in erecting the modules, one upon the other, the angled end faces tend to "center" the modules with respect to the one below it. Then by mere insertion of one bolt 24 in one of the mating connector tubes of that module, the entire module is stabilized until the other bolts are inserted in the other connector tubes.

The cavity in the connector tubes 22 and the diameter of bolts 28 may be of any reasonable dimension. Typically, a 3/8-inch bolt is used with a 13/32-inch inner diameter connector tube. Using high strain steel for bolts 24, a 3/8-inch bolt has a sufficiently large root area that it can safely be tightened to develop approximately 12,000 pounds tension. This is normally sufficient to resist normal wind or other loads on a tower.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention, which, as a matter of language, might be said to fall therebetween.

Claims

Now that the invention has been described what I claim is:

1. A skeleton tower comprising a plurality of vertically stacked, modular sections, each section including a plurality of vertical legs spaced about the periphery thereof, the vertical legs of one section being in aligned, end-abutting relation with the legs of the adjacent section, means connecting the legs together at the abutting ends, said means comprising a connector tube fixedly connected to each end of each leg, the tubes at the abutting ends of the legs forming a pair, the longitudinal axes of the tubes being in angular relation to the longitudinal axes of the legs, the pair of connector tubes at the abutting ends of the legs being aligned with each other, and fastening means traversing said tubes and clampingly joining the tubes together.

2. The structure of claim 1 wherein said fastening means comprises nut and bolt combination including a bolt positioned on the interior of the pairs of connector tubes, and a nut lockingly engaging one extremity of said bolt so as to be maintained in frictional engagement with one end of one of said tubes, whereby said tubes are maintained in locked, aligned engagement with one another.

3. The joint structure of claim 1 wherein said pairs of connector tubes have abutting end faces which are angular to a horizontal plane.

4. The joint structure of claim 1 wherein said pairs of connector tubes have abutting end faces which are in a horizontal plane.