Working platform

The boom of a crane carries a pivot bearing for a second bearing which guides an elongated column. The upper or the lower end of the column supports a gallery which is turnable about its axis. The second bearing is pivotable about the horizontal axis of the pivot bearing by a cylinder-and-piston unit, and the column is movable lengthwise with respect to the second bearing by the crane cable.

BACKGROUND OF THE INVENTION 
The present invention relates to a working platform with a gallery which is 
mounted on a column and is turnable about the longitudinal axis of the 
column, which column is axially movably mounted in a shifting bearing and 
the shifting bearing is pivotably mounted in a pivot bearing for movement 
about an axis which is oriented transversely of the longitudinal axis of 
the column, and with a mobile boom which is turnable about a vertical axis 
with the pivot bearing mounted at the end of the boom. 
A working platform of such type is known as a bridge inspection apparatus 
and is described, for example, in German Pat. No. 1,216,914. Owing to 
their specific construction, such single-purpose apparatus cannot be 
utilized for the cleaning of facades of tall buildings or the like. It is 
already known to employ mobile single-purpose apparatus, known as 
"skyworker", for work on the facades or the like. Such apparatus consist 
of several articulately connected arms the last of which carries at its 
free end a basket for one or two workers. A drawback common to both 
single-purpose apparatus is that their field of application is limited; 
this results in undesirable cost-producing idle times which must be 
charged to the hours of productive use. 
OBJECTS AND SUMMARY OF THE INVENTION 
An object of the present invention is to provide a working platform which 
can be used as a bridge inspection apparatus as well as for the cleaning 
of facades or the like. 
In accordance with the invention, this object is achieved in that the 
mobile boom is a pneumatic crane and that the column is provided with a 
fastening point for the end of the crane cable for the purpose. of lifting 
or lowering the column in the shifting bearing by means of the crane 
cable. 
The invention brings about the advantage that one can employ commercially 
available automatic cranes so that a new field of application is opened 
for such types of cranes.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A plate 3 is secured by means of four braces 2 (only two shown in the 
drawing) to the upper end of a preferably telescopically extendable boom 1 
of a pneumatic crane. The plate 3 comprises six projecting lugs 4 which 
are disposed in two rows, one behind the other. The lugs 4 of each row are 
provided with coaxial bores for reception of one insertable pin 5 each. 
Each lug 4 corresponds to a lug 6 which latter lugs are secured to a plate 
7. The insertable pins 5 further extend through coaxial bores of the lugs 
6 so that they separably but securely couple the plates 3 and 7 to each 
other. A pivot bearing 9 is secured to the plate 7 by means of braces 8, 
and a second bearing 11 is pivotably mounted to the bearing 9 for movement 
about a shaft 10. A column 12 is axially movably mounted in the bearing 11 
and has a pivot pin 13 at its lower end. An outwardly extending carrier 14 
is mounted on the pivot pin 13, and this carrier supports a gallery 15. 
The gallery 15 consists of one or more parts which can be assembled so 
that the length of the gallery can conform to given requirements. The 
lower end of the column 12 carries a ring gear 16 which meshes with a gear 
17 fixed to a shaft 18. The shaft 18 is rotatably journalled in the 
carrier 14 and its upper end carries a hand-operated crank wheel 19. By 
rotating the crank wheel 19, the persons occupying the gallery 15 can 
swing the latter about the column 12. 
A cylinder-piston unit 20 is provided to turn the bearing 11 about the 
shaft 10. The cylinder of the cylinder-piston unit 20 is articulately 
connected to the plate 7 and the piston rod is articulately connected to 
the bearing 11. By means of the cylinder-piston unit 20, the column 12 can 
be oriented and held in a vertical position independently of inclination 
of the boom 1. A roller 21 is rotatably mounted on the plate 7. 
Furthermore rotary rollers 22 and 23 are respectively provided on the 
shaft 10 and at the lower end of the column 12. A crane cable 24 is 
trained over the rollers 21, 22 and 23 and is secured to the shaft 10 by 
load hooks, not shown. In this manner, the column 12 can be lifted or 
lowered by the crane cable without resorting to a separate drive. 
In the example of FIG. 3, similar reference characters denote parts which 
are identical with or equivalent to those in the example of FIG. 2. In 
contrast to the first example, the gallery 15 is secured here at the upper 
end of the column 12 which effects a further increase of the working 
height. 
As indicated in FIG. 1 by broken lines, a second load hook which is 
provided on the crane can be used to lift working equipment, working 
material or the like onto the gallery 15. 
In accordance with an embodiment which is not shown, two galleries can be 
disposed in parallel one above the other. This embodiment will be employed 
with preference for washing of building facades.