Device for wind bracing the members of a lattice mast and lattice mast provided with said devices

The invention relates to a device for wind bracing of the vertical members of a lattice mast. It is characterized in that it is provided at its ends (5, 6) with detachable means (8, 9) for joining it to its vertical members, which in turn are provided with complementary means (10).

RELATED APPLICATIONS 
This application is related to the following applications filed 
concurrently herewith: 
1. "Cylindrical Mast Element For End To End Assembly with Other Elements So 
As To Constitute a Mast", Guy Guislain and Yves Foissac, U.S. Ser. No. 
745,934, now U.S. Pat. No. 4,656,804 corresponding to French application 
No. 84.09.998. 
2. "Device for Raising A Mast And Mast Raised With The Aid Of Such A 
Device", Jean Paul Perek, U.S. Ser. No. 745,937, now U.S. Pat. No. 
4,677,444 corresponding to French application No. 84.10.002. 
3. "Articulation Device Of A Mast And Mast Articulated With This Device", 
Guy Guislain, U.S. Ser. No. 745,933, corresponding to French application 
No. 84.10.001. 
The subject matter of each of said related applications is hereby 
incorporated by reference. 
FIELD OF THE INVENTION 
The present invention relates to a device for cross-bracing or wind bracing 
the members of a lattice mast, as well as to a lattice mast provided with 
such wind bracing devices. 
The invention relates more particularly, but not solely, to masts intended 
for supporting provisional broadcastirg or receiving antennas of 
considerable weight, such as certain antennas used for military or 
civilian purposes, at a great height above the ground, for instance 30 to 
35 meters. 
BACKGROUND OF THE INVENTION 
Taking into account the height and weight of these antennas, their mast 
must be capable of withstanding considerable strain. Very strong girders 
therefore become a necessity. 
To this end, instead of a mast of the standard type, embodied by a sole 
vertical member, which for the sake of strength must have an excessively 
large cross section and weight, masts having latticework girders are 
generally used, and these masts are therefore commonly known as "lattice 
masts". 
These lattice masts comprise at least three vertical members, which are 
generally cylindrical and which are held together by a triangulation 
embodied by wind bracing devices, each of which is associated at its ends 
with two of the vertical members at points which embody assembly 
junctions. 
To facilitate transporting them, it is known for these lattice masts to be 
embodied in a plurality of sections. 
At the site where the mast will be used, the sections are then laid on the 
ground so they can be assembled end to end. Then the assembled mast is 
raised vertically, and it is kept in this position by a bracing system. 
Each of these mast sections comprises three assembly parts joined by wind 
bracing devices corresponding to this part of the mast, which thus becomes 
a unit that can no longer be dismantled. 
When they are used, these sections are simply placed end to end and 
assembled by some known means, such as a bolted connection, at each end to 
end junction. 
Unfortunately, aside from the fact that a special machine, such as a crane, 
must be used to raise them, such masts have the disadvantage of being 
bulky, because each section is in the form of a latticework iirder having 
a cross section of considerable bulk. 
In the case of the standard mast, comprising a single vertical member, the 
problem of great length is comparable and is likewise solved by embodying 
the member in a plurality of sections assembled end to end upon being 
used, and the problem of large cross-sectional bulk is also present, 
although less acute. Nevertheless, it is not at all necessary to use a 
machine to raise the mast, because for this kind of standard mast it is 
sufficient to mount the antenna on the top element, and then to insert 
this top element into a vertical guide shaft which is placed a certain 
distance above the ground, via a supporting framework; then, in order to 
raise the antenna to the desired height, the additional elements 
successively engage the bottom of the shaft, which progressively raises 
the top of the mast. 
Unfortunately, with the lattice masts known at present, even if they are 
divided into a plurality of sections it is impossible to use this method 
to erect them, because the means for joining the sections and their wind 
bracing devices prevents their translation in a shaft; furthermore, taking 
into account the cross section of the lattice mast, this shaft would be of 
excessively large dimensions. 
OBJECT AND SUMMARY OF THE INVENTION 
If is accordingly an object of the present invention to devise a lattice 
mast which is less bulky to transport. 
A further object of the invention is to make it easy to erect such a mast. 
To this end, the wind bracing device according to the invention is 
characterized in that it is provided at its ends with detachable 
connecting devices for attachment to the vertical members, which in their 
turn are provided with comparable devices. 
The subject of the invention is a lattice mast provided with these devices. 
The invention will be better understood from the ensuing description of a 
preferred embodiment, given as a non-limiting example, taken in 
conjunction with the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Turning now to the drawings, and particularly FIGS. 1 and 4, the lattice 
mast 1 includes at least three vertical members 2.sub.a, 2.sub.b, 2.sub.c, 
which are cylindrical and have parallel axes and are held together by a 
triangulation (see FIG. 5) formed by the wind bracing devices 4, which are 
joined at their upper and lower ends 5 and 6, respectively, to two of the 
vertical members at points 7 representing assembly junction points. 
FIG. 1 shows, in schematic form, the entire structure as assembled, and 
FIG. 4 shows a portion of the lattice mast assembly in more detail. 
The vertical members are preferably connected in pairs by networks 3 which 
are distinct from the wind bracing devices and are arranged in zigzag 
fashion, one after another, in planes parallel to the planes in which the 
two vertical members are located. 
According to an essential characteristic of the invention, the wind bracing 
or crossbracing means 4 are provided at their ends 5, 6 with detachable 
means 8, 9 for joining with their vertical members, which are in turn 
provided for this purpose with complementary means 10. 
According to another characteristic of the invention: 
first, the complementary means carried by the vertical members comprise 
holes 10 each of which is radial to the axis of its vertical members and 
perpendicular to the plane of the two members connected by these devices; 
and 
second, the means 8 of one of the ends 5 comprises a cylindrical pin 11, 
having a diameter corresponding to that of the radial holes in the 
vertical members, one of which is traversed, during assembly, by said pin, 
while the means 9 at its other end 6 comprises a hole 12 having an axis 
parallel to that of the pin 11 and a diameter corresponding to that of the 
pin and which, during assembly, receives the pin 11 of the contiguous wind 
bracing device. 
To this end, the pin has a length sufficient for it to be able to traverse 
one of the two pieces, that is, the vertical member and the wind bracing 
device, and to engage the other piece at least partially. 
According to another characteristic of the invention, each pin 11 has a 
free end 13 which is provided with a means 14 cooperating with a 
complementary means 15 carried by the hole 12 of another wind bracing 
device, so as to interlock them. 
The means 14 with which the free end 13 of the pin is provided comprises a 
circular throat 16 communicating with a groove 17 which is substantially 
of the same size and the same depth and extends from the throat 16 to the 
free end 13 of the pin, while the complementary means 15 with which the 
hole 12 is provided comprises a prong 15 forming an projection having 
dimensions corresponding to those of the throat 16 and the groove 17. 
Because of this, the pin cannot engage the hole or be removed from it 
unless it is in a position of alignment determined by the relative 
positions of the groove 17 and the prong 15. 
It is thus sufficient for this position to be different from that in which 
the device is placed after being mounted on the vertical members to assure 
self-locking. 
Each vertical member may be realized in a plura1ity of sections 20, 21, 22, 
which upon assembly are joined end to end. 
In this case, before the wind bracing devices are put in place, these 
vertical members 2.sub.a, 2.sub.b, 2.sub.c can be erected by guide shafts 
23, 24, 25 in the manner similar to that used for conventional masts. 
The shafts 23-25 are then joined by a support 26 resting on the ground via 
a suitable supporting framework 27 so that via the bottom of each shaft, 
it will be possible to add the vertical member elements in order to attain 
a mast of the correct height. 
Preferably, one element at a time is added to each vertical member, and 
then the wind bracing devices are put in place, before recommencing the 
operation. 
However, instead of joining the vertical member elements which are located 
at the same height in the mast, it is provided according to a 
characteristic of the invention that each wind bracing device, at its 
ends, join one vertical member element with another vertical member 
element which, (i.e., next higher or next lower) in the finished mast, 
will be located at a contiguous level, as can be seen in FIGS. 1 and 4.