LBT PROJECT 2x8.4m TELESCOPE
	TECHNICAL SPECIFICATION OF THE MEASURING HEADS, AUXILIARY DRIVE, STOW PINS AND LIMIT SWITCHES
	Doc. 401A006/B Dr.Eng.Raffaele Tomelleri

INDEX:

1. Introduction.
2. Supply Description.
3. List Of Enclosed Drawings.
4. Acceptance Tests.
5. Delivery.

The present document groups together a certain number of electro - mechanical auxiliary units that complete the AZ and EL axis measuring and driving systems.

These items are included in one only Request for Quotation document because of the similar accuracy and quality of machining demanded, but, much more important, they are very much interfaced with the problem of their supports machining and the adjustment of their position, problems to be discussed and agreed with the Company that shall be charged of the shop pre - assembly of the whole telescope.

2 - SUPPLY DESCRIPTION -

2.1 - 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.

2.2 - Hardware supply.

2.2.1 - Measuring System -

The supply consists in the measuring heads supports and the anchoring and tensioning auxiliaries for the tapes fixation of the FARRAND strip encoders selected and purchased by the P.O.. The only technical point we underline here is the preload of the bearing guiding each reading head must be of 20 N.

As usual, the fixation screws or bolts for the auxiliaries shall be supplied by the Company pre-assembling the telescope in the shop; as at the pre-assembling not all the electronic control system of P.O. supply shall be installed and tested, the Manufacturer shall be asked to demonstrate the correct anchoring and housing of the strip encoder using a dummy section of the same that shall be supplied by the P.O. to verify the mechanical interfaces according to the assembly procedure prepared by the encoder Manufacturer.

All the Lay out system drawings included in this specification are the original assembly drawings generated during the mechanics definition and are not correct according the final structural design of the telescope , so with the order the Manufacturer shall be given also the structural involved drawings to verify the correct interfaces.

2.2.2 - AUXILIARY DRIVES -

In this specification is included the supply of two auxiliary driving units, one for each of the EL rolling sectors, that shall be positioned and fixed at the shop pre-erection of the telescope according the enclosed lay out drawings.

Provided that the scope of the units is to grant the control of the EL mount in the event that the main drive should be out of service or during the early phases of the telescope pre-erection, their dimensioning has been foreseen at the limit of the transmissible load by the gears teeth to allow the rotation when the structure is unbalanced.

We recall here the max. unbalance of the EL axis that can be controlled by the auxiliary drives at the stress limit of the gear teeth, i.e. 100.000 N x 7,05 m x 2 = 1.400.000 Nm -

The supply of this specification includes the two driving units complete of the hydraulic motor, hand insertion joint of the pinion with the relevant limit switches; at the charge of the shop pre - assembling Manufacturer are the fixation bolts, the pipes and accessories to connect the motor to the hydrostatic supporting system plant and the temporary electric connection cables for the tests.

2.3 - STOW PIN -

The two stow pin units must be supplied complete of the relevant driving units and the limit switches sensing directly the pin position .

At the charge of the shop pre - assembling of the telescope is the supporting frame including the anchoring plates for the end stops and the fine adjustment of its position compared with the holes machined on the rolling sectors structure.

2.4. - END STOPS -

Although defined and positioned on the same assembly drawings of this group of mechanic these items shall be procured and assembled by the shop pre - erection Manufacturer, being mandatory the selected type, product by Domange-Jarret Co..

2.5 - SURFACES PROTECTION -

For all the above items all the machined surfaces, after positive acceptance tests, must be protected with grease SKF LGMT 2/5 or other equivalent product.

The supports or structural gear boxes must be sand blasted SA 2,5 before machining and protected with one layer of primer 100 µ thick and a final one, after machining and proper cleaning, 70 µ thick; the colour shall be communicated with the order.

2.6 -Environment conditions.

· Storage temperature	-30 a +50 °C
· Operating temperature	-15 a +25 °C
· Storage pressure	500 a 760 Torr
· Operating pressure	600 a 600 Torr
· Storage humidity	a 80 %
· Operating humidity	5 a 95 %

3 - LIST OF ENCLOSED DRAWINGS -

The following drawings are enclosed together with this specification:

Dwg. 430A010/B - AZIMUTH GENERAL ASSEMBLY PLANT VIEW

Dwg. 500A010/B - ELEVATION GENERAL ASSEMBLY ZENITH POSITION

Dwg. 500A011/B - ELEVATION GENERAL ASSEMBLY HORIZON POSITION

Dwg. 440A015/B - ELEVATION SUPPORT VIEW

Dwg. 462A010/B - AZIMUTH DRIVE APPLICATION TRACK SECTION

Dwg.470A011/B - AZIMUTH MEASURING SYSTEM LAY OUT

Dwg.470A010/B - AZIMUTH MEASURING SYSTEM

Dwg: 530A011/B - ELEVATION MEASURING SYSTEM LAY OUT

Dwg. 530A010/B - ELEVATION MEASURING SYSTEM

Dwg. 523A011/B - AUXILIARY DRIVE

Dwg. 523A010/B - STOW PIN AND AUXILIARY DRIVE

Dwg. 524A010/B - STOW PIN

4 - ACCEPTANCE TEST -

All the subassemblies included in the present Specification shall be checked, according to the quality control plan of the Manufacturer and agreed by the P.O., witnessing the designer or the P.O. representative. The control shall be dimensional for all and functional for the auxiliary drives and stow pins.

5 - DELIVERY -

All the material subject of the present Specification must be delivered, Truck transport packaged, to the Company that shall be charged of the shop pre-erection of the whole telescope.