T E C H N I C A L S P E C I F I C A T I O N
W. Gallieni, ADS Italia
301a003d
The construction of the rotation bogies and drives is the main mechanical part of the LBT Project Telescope Rotating Enclosure.
To simplify the construction and machining of the circular rail (23 m in diameter), it has been designed as a flat top rail, and is necessary displacing the centre convergence point of the wheels axis at the same level of the rail top, inclining the bogies and wheels axis of half the cone in which are machined the wheels contact surfaces.
This is the normal solution used in the design of the big radio telescopes azimuth axis rotation drives, and requires only an accurate procedure during assembling and pre-alignment in shop and at the final assembling at the erection Site.
The connection flanges between the upper surface of the main equalising beams and the building legs, also if have been located at the same level to easier the interfaces design, are the detail that needs a very good agreement and understanding with the building Manufacturer, because of the decision of how transmitting the horizontal shear forces and the positioning procedure that defines the tolerances in the fixation bolts bores.
For reasons of standardisation of the electro-mechanical components
present in the various subsystems of the rotating enclosure, the
P.O. shall order and delivery at his charge to the bogies Manufacturer
the nine motor - reducer units (eight to be assembled and one
spare).
2. TECHNICAL DATA AND DRAWINGS-
2.1. General technical data-
- Circular track nominal diameter 23,00 m
-Rail useful width 140,0 mm
- Circular track max. runout 2 mm
- Enclosure nominal rotation velocity = 1,5 degree/sec = 0,25 rpm
- wheel ( 100 cm diameter) nominal speed = 5,75 rpm
- Wheels total number = 20
- Motors n. 8 x 12,5 KW / 4 poles ( 2 each bogie)
-estimated weight for one four wheels bogie 22200 kg
-estimated weight for one six wheels bogie 32900 kg
- estimated weight of the materials to be supplied, excluding
the
driving units supplied by P.O. 97000 kg
To help the Manufacturer in the preparation of the shop drawings,
the Technical Specification shall be integrated with the Technical
Report 301a002 resuming all the loads
transmitted on the wheels in the various working conditions.
2.3. Drawings. The following drawings are enclosed
together with this specification.
Dwg. 341A000/B REAR AND FRONT BOGIES ASSEMBLY -
Dwg. 341A001/B HORIZONTAL GUIDE ROLLERS
Dwg. 341A002/B DRIVE WHEEL ASSEMBLY
Dwg. 341A003/A STOW PIN ASSEMBLY
Dwg. 341A004/B LEG BOTTOM FLANGE CONNECTION TO BOGIE
Dwg. 341A009/A DRIVING UNITS TORSION REACTION ARM
TYPICAL ASSEMBLY
Dwg. 341A010/A TORSION REACTION ARM - TYPICAL DETAIL
Dwg. 341A006/B ENCL. DRIVE MECH. - PLANT GENERAL
Dwg. 341A007/B ENCL. DRIVE MECH. - LATERAL SECTION
3 .SUPPLY DESCRIPTION.
3.1 - Shop Drawings, planning and technical documentation.
This is the first activity to be performed by the
Manufacturer and shall be performed according what specified in
the "Statement of Work", attachment A of the RFP.
3.2 - Supply Limits -
The supply includes the construction and the machining of the
steel structure of the various equalising beams and wheels supports,
and the supply and integration of the wheels, articulation axis,
bearings and all the necessary mechanical accessories. Also included
in this supply is the integration of the eight motor/ reducers
driving units that shall be supplied by the P.O.
The Supplier shall preassemble the four bogies groups - n. 2 four
wheel units and n.2 six wheel units -, checking their radial alignment
and convergence toward the centre of the rail circular track.
In each of all the main articulation shafts of the group will
be foreseen a through centre hole, about 20 mm diameter with the
attachments for the collimator for the convergence verification.
The gear / motor units supplied by the P.O. shall be connected,
at the care of the Manufacturer, to the relevant bogie frame through
a torsion reaction arm, the typical assembly drawing is included
in the tender documents.
The Manufacturer of the Bogies shall supply to the care of the
Manufacturer of the Rotating Enclosure a set of four machined
plates. These steel plates, of thickness TBD, shall act as templates
for the connection borings between the top part of the central
frame of the bogies and the lower part of the building legs. After
assembly of the Rotating Enclosure steel frame on the bogies,
these plates shall also be machinable as shim plates to make final
adjustment of the angle of the connections between the building
legs and the bogies.
With reference to the possible erection and Site alignment procedure
- see dwg.341a006 and 341a007 -, the Manufacturer shall include
in his supply also the eight adjustable temporary anchoring tie-rods
to the telescope pier.
3.3. Surface protection and Painting.
After the stress relieving heat treatment and sand blasting SA
2.5 , all the surface of the bogies structure, must be protected
with Primer (125 micron thickness), before machining.
After machining and careful cleaning must be applied a second
layer of epoxy type paint (100 micron thickness) on all the
inside and outside surfaces
3.4. Packing.
The packing of the units must be described in detail in the supply
offer foreseeing that the same shall be shipped by sea (in the
case of European Supplier ) and than transported by truck to the
staging area in Safford Arizona. The bogies may be stored outdoors
in the staging area for several months before they are installed
on the mountain.
3.5. General rules.
The supply must comply with the 89 / 392 / CEE rules.