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Answer 2. Drawing 341a009, as indicated on the label and the technical description, is only a "typical" drawing to illustrate how the reaction arm for this type of gear box can be designed, but does not represent our particular gear and bogy. Drawing 341a000 shows exactly the gear and motor assembly we are going to adopt for the LBT bogies.
We underline also that the gear / motor units are not part of the bogies RFP, but are parts that shall be supplied by the LBTPO for the integration.
(received 19 June 1997)
What are your ultimate tensile and yield strengths of material needed to handle the load design? We have found no specifications of materials listed. i.e.: (Plates for fabrication, Rounds for axles, Wheels- should they be rim toughened or deep hardened?)
Answer 3. Materials:
Answer 4. We will shortly provide a sketch of the welding details of the main weldments. For the main connections between the web and the top and the bottom flanges we request a single or double bevel preparation for full penetration welding in the center most stressed areas and a good penetration proportional to the thickness of the plates for the full length --- like in all these types of structures.
The sketch is available as a new revision of drawing 341a000c.dwg.
Answer 5. For the materials, the quality certificates of the steelwork are sufficient. For welds, ultrasound or penetrating dye tests should be used. We expect the proposal of the quality control from the Supplier. Remember that these structures are requested all stress relieved before the machining.
Answer 6. These rules are the European safety and quality rules that every European manufacturer must comply with. They include also the operational and maintenance manuals described in the Statement of Work. Non-European manufacturers need not follow these rules for LBT, provided that the meet the other requirements of the Statement of Work.
Answer 7. There is no proposal number only a proposal name which in this case is "Enclosure Rotation Bogies and Drives".
Answer 8. The engineering responsibility of the Supplier is for the shop drawings and the details of the mechanisms. Successful execution of these details requires good experience in the design and construction of these types of mechanisms. The LBTPO and the design engineers of the enclosure and bogies take responsibility for the overall loads and the interaction with the structure of the Rotating Enclosure and the Circular Rail. These loads were summarized in the Technical Report on Rotation Bogies and Drives (301a002). An additional report is being prepared which summarizes the dimensioning criteria for the various sections and axes of the bogies.
Answer 9. The equivalent American steel to "C40 UNI 7478" is "AISI 1040". For UNI standards see: ENTE NAZIONALE ITALIANO DI UNIFICAZIONE the Italian National Standards Body.
Answer 10. The bronze nut is of the most common material you can find on the market. This is a mechanism that has only gravity to balance.
Answer 11. (see also Answer 3 above. The equivalents have proven difficult to sort out. We are still working on this problem.)
Answer 12. It is only the difference represented by the n.8 driving units (GEARS AND MOTORS) that shall be supplied by the LBTPO, so not part of the supply of the Bogies Manufacturer.
Answer 13. Our goal is having the axis of all the wheels of one bogie included in a circle of 1 mm diameter positioned in the center of the rail at the level of the top of the rail. What we are expecting to find in the proposal is the tolerance the Manufacturer can guarantee and the method proposed to achieve this tolerance.
A new drawing has been created to show how an alignment telescope might be mounted on the wheel axis. This drawing is 341a011.
Answer 14. The small motor driving the stow pin is 0,37 kW -- 4 poles, European size 71B, flanged to a worm gear reducer size 63.
Type UM1451152 Rubber Packing is a standard rubber seal that you can buy for a shaft to protect the inside guided length from dirt.
Answer 15. Yes, we will agree to extend the proposal deadline for the proposals regarding Enclosure Rotation Bogies and Drives by one week. The new deadline will be July 30, 1997.