ROTATINGSUPPORTINGARMS.docx

1、ROTATINGSUPPORTINGARMSLBT PROJECTTECHNICAL SPECIFICATIONROTATING SUPPORTING ARMSWITH THE FABRIC RETRACTABLE COVEROF THE PRIMARY MIRRORS1 SUPPLY DESCRIPTION. 41.1 Rotating Arm with Driving system 41.2 Retractable Fabric Cover 41.3 Supplying consistence 52 AMBIENT WORKING CONDITIONS 53 TECHNICAL DATA

2、AND DRAWINGS 63.1 Rotating Arm See dwg. 727a008 63.2 Retractable cover See dwg. 727a009 63.3 Electric cabinets and control 64 LIST OF DRAWINGS 84.1 List of assembly drawings 84.2 List of subassembly drawings 85 SUPPLY RULES. 105.1 Planning 105.2 Procedure 105.3 Surface protection and painting 105.4

3、Delivery F.O.B. 106 ACCEPTANCE TESTS 11INTRODUCTION The dust and any type of dirty depositing on the Primary Mirror surface, are cause of dangerous loss of efficiency of the Telescope, so much to suggest, also if with a increase of cost and complication, to include in the design an effective cover p

4、rotection for the M1. The present specification concerns the two covers for the primary mirrors of the telescope, one for the right side and the other for the left one. Each of them has a main rotating arm to get it in position and a deployable umbrella (cover) driven by different control. As can be

5、 understood from the enclosed drawings, each unit is described as two separate components. In fact, the rotating arm with its drive system presents construction problems quite different from the retractable fabric cover with its guiding and driving system. The contract for the entire supply will be

6、given to a single Company. The principle and the construction technology of the fabric retractable cover has been proved and positively tested during 1995 by the Arcetri Observatory on a 2 m diameter scaled prototype. The dimensions reported in the related drawings must be strictly respected because

7、 of the interfacing telescope structures and the optical obstructions. On the other hand, the construction details for the cover and its guiding system are subject to alternative proposals according to the experience and suggestions coming from the Manufacturers.1 SUPPLY DESCRIPTION.1.1 Rotating Arm

8、 with Driving system This first subassembly of the M1 Cover consists in a fixed cylindrical mast to be bolted on the EL structure, supporting both the bearing and the screw jack for the 90 degree rotation of the swing arm - see dwg.727a009 and 727a008. Although on the dwg 727a011 also the driving un

9、it and the chain for opening and closing the cover are represented, we include in the mechanical supply description only the machined circular sector supporting the closed bellow, while all the details described in the introduction are included in the cover item. The two arms hinged in the center ha

10、ving the function of mobile anchoring of the bellows and support of the driving unit for opening and closing it, are part of the retractable cover item as well. An important interface is on the EL main structure, consisting in the supply of a template complete of the borings for the fixation of the

11、cylindrical column represented on the dwg. 727a013. 1.2 Retractable Fabric Cover To complete the M1 Cover unit - see the assembly dwg. 727a007 - has to be added what we have called “fabric cover”, such item includes a large series of mechanical details, starting from the chain to be fixed around the

12、 external cell wall and the two driving units with the relevant supporting arm hinged at the center pin. The cover itself is foreseen being made of a series of stainless steel thin blades connected each other with hinges all along their length. The first and the last blade are connected to the fixed

13、 and driving structures; particular attention must be devoted to the details of supporting and guiding the cover blades around the M1 cell upper flange, to the blades themselves supporting the horizontal and front fabric connections. As far as the supports and connections around the center pin are c

14、oncerned, a sufficient number of hinges connect to a bush rotating around the center pin itself. Such design reported in the enclosed drawings can be revised also according to the Manufacturer experience, considering that we have represented the results of the first 2m diameter test bench implementa

15、tion.1.3 Supplying consistenceMore in detail, the supply consists purchasing all the commercial components being part of the rotation mechanisms, the motors and the limit switches; also the final cabling and the electrical control units are part of the supply. The necessary equipment for the accepta

16、nce tests shall be provided by the supplier too.Every rotating M1 Cover shall be fully preassembled including the rotation mechanisms and located for the acceptance functional tests in horizontal position (telescope zenith pointing) and at different elevation angles toward the vertical position.2 AM

17、BIENT WORKING CONDITIONSThe M1 Covers are required to grant the performance in the following environment conditions: - Operating temperature - 20 + 25 C - Operating pressure 500 600 Torr - Operating humidity 5 95 % - Storage temperature - 30 + 50 C - Storage pressure 500 700 Torr - Storage humidity

18、5 80 % - Altitude 3,250 m a.s.l. - Lifetime of the Telescope exceed 25 years3 TECHNICAL DATA AND DRAWINGS3.1 Rotating Arm See dwg. 727a008 Max. speed of the nut on the screw 0,45 m/min Displacement of the nut for 90 arm rotation 0,6 m Time demanded for positioning the arm max 2 min Driving motor for

19、 each of the two sectors of the bellow: 4 KW / 4 poles with disk brake 480V/60Hz Screw Jack UNIMEC TYPE TPRC 559 1 / 30 with screw and nut on re-circulating balls and elastic protection of the screw.o Estimated weight of the fixed mast supporting the driving Jack 293 kg o Including the mechanical de

20、tails 400 kgo Estimated weight of the rotating arm supporting the bellow with the auxiliary structure 710 kgo Estimated weight of the cantilever arm supporting the driving arms of the bellow 540 kg3.2 Retractable cover See dwg. 727a009 Driving units:o N 2 Motors WACO RS 500 BT 2 Nm Cont. torque, wit

21、h brake and tachogeneratoro N 2 Gearbox PLC120 GSC - Ratio 1:120o N 2 Chains sprockets 13 teeth for chain 1 inch pitch o Chain fixed around the cell on a 9400 -1 “ pitch o Driving sprocket velocity 2500 / 120 = 20,8 rpm o Time requested for opening / closing the cover 2.5 Material used for the 2m co

22、ver test Kevlar Preox 270 g/m2- Produced by the French Company DICKSON PTL -3.3 Electric cabinets and control According to the main data of the motors listed above and the limit switches logic, it is required a simple analog command control for moving the Rotating Arm and the Retractable Cover. In d

23、etails well have: direct power supplying for the motors according to the required voltage, safety devices for the motors (over current, thermal switches), one push button command, for each direction, moving the rotating arm to the requested position (working position / resting position), one push bu

24、tton command, for each direction, moving the retractable cover for each direction (open / close), both positions of the two arms will be monitored by on/off lights, the limit switches control the power to the motors and the lights status. 4 LIST OF DRAWINGS4.1 List of assembly drawingsDwg. 727a007 -

25、 M1 cover - General assemblyDwg. 727a008 - M1 cover Rotating arm with driving systemDwg. 727a009 - M1 cover Arms cover with guiding and driving systemDwg. 727a011 - M1 cover Retractable fabric cover with center anchoring4.2 List of subassembly drawingsDwg. 727a012 - Drive unit assemblyDwg. 727a013 -

26、 Fixed cylindrical columnDwg. 727a014 - Screw jack supportDwg. 727a015 - Rotating boxDwg. 727a016 - Sector for chain jointDwg. 727a017 - Rotating armDwg. 727a018 - Circular sectorDwg. 727a019 - SpacerDwg. 727a020 - AdjustmentDwg. 727a021 - Cross beamDwg. 727a022 - Bearing supportDwg. 727a023 - Beari

27、ng cupDwg. 727a024 - Cross beamDwg. 727a025 - PinDwg. 727a026 - WasherDwg. 727a027 - Bearing supportDwg. 727a028 - Screw jack UNIMEC TPR559Dwg. 727a029 - SectorDwg. 727a030 - Fixed sectorDwg. 727a031 - Drugging sectorDwg. 727a032 - Anchoring plateDwg. 727a033 - Upper anchoring sectorDwg. 727a034 - L

28、ower anchoring sectorDwg. 727a035 - Spacer tubeDwg. 727a036 - Screw M8x45Dwg. 727a037 - SpacerDwg. 727a038 - HingeDwg. 727a039 - Anchoring tube assemblyDwg. 727a040 - Anchoring tubeDwg. 727a041 - Anchoring tubeDwg. 727a042 - Joint M8 right threadDwg. 727a043 - Joint M8 R/L threadDwg. 727a044 - Bronz

29、e ringDwg. 727a045 - Anchoring tie assemblyDwg. 727a046 - Special nutDwg. 727a047 - Special washerDwg. 727a048 - ArmsDwg. 727a049 - Support for drive unitDwg. 727a050 - Chain supportDwg. 727a051 - Protection coverDwg. 727a052 - Bushing self lockingDwg. 727a053 - SpacersDwg. 727a054 - Roller chain su

30、pportDwg. 727a055 - Safety washerDwg. 727a056 - PinDwg. 727a057 - Washer Dwg. 727a058 - Bushing self lockingDwg. 727a059 - PinDwg. 727a060 - Tie rodDwg. 727a061 - WasherDwg. 727a062 - WasherDwg. 727a063 - Coupling flangeDwg. 727a064 - CouplingDwg. 727a065 - ShaftDwg. 727a066 - Bearing supportDwg. 72

31、7a067 - Bearing coverDwg. 727a068 - SpacersDwg. 727a069 - SpacersDwg. 727a070 - Chain jointDwg. 727a071 - SprocketDwg. 727a072 - Simplex chain5 SUPPLY RULES. The construction of the M1 cover must comply the following rules:5.1 PlanningThe Manufacturer shall submit to the P.O. a detailed planning of construction, pointing out the intermediate tests and verifications foreseen by its Quality Control Service.5.2 ProcedurePreparation of all procedures and methods to execute the critical operations of the manufacturing.5.3 Surface protec