NOVEMBER 10th  2005:       QUAD INSTALLATION FIXTURES

1.1 INTRODUCTION               
The following updates the status of the quadruple pendulum installation fixtures outlined in LIGO-T050071.
Ken Mailand, Oddvar and Calum Torrie have been working on developing this design for manufacture.
As such we have simplified some of the design and would like to suggest an alternative to the Air Bearing and XY translation stage.  

1.2 EXISTING SET UP
As can be seen on the base table, in figure LIGO-D050291 below, sits a fixture assembly  that will move in X and Y and tilt to locate the Quad suspension. The existing layout shows an air bearing set-up modified for the suspension installation, and made from the original chamber external suspension assembly also reference the two pictures below.


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All of the parts shown in this sketch are now being manufactured with Mike Gerfen in CES at Cal tech.

It should be noted that the support plate with rotational alignment, reference page 6 of LIGO-T050071-00, is not shown in this configuration. With Oddvar's approval Ken and I have simplified this design and Ken  is currently working on the drawings for this modified design.


LIGO-D050291-B  (click on sketch)
 
NOT SHOWN
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ROTATIONAL ADJUSTMENT
 AIR BEARING (AT LHO)

XY TRANSLATION STAGE (AT LHO)

altfix

ALTERNATIVE FIXTURE (CLICK ON IMAGE)

        

                   

1.3 PROPOSED ALTERNATIVE
An alternate plate fixture assembly uses flat plates with cam rollers, and pivot shafts, to accomplish the same locating movements as the air bearing & XY set-up above.

We believe the improvements in the alternative design are as follows: -

1. The range of motions in the plate fixture are larger especially the tilt, and rotation.  We believe this will eliminate fine pre-staging the suspension, to match the table or beam orientation 

2. The use of the plate fixture assembly does not require an air supply inside the chamber for the air bearing operation. The air bearing set-up requires careful operation, there is the possibility of scratching the critical surfaces, without air in the system.

3. Due to its compact design the plate fixture assembly can be used on the genie lift, outside the chamber.

4. The plate fixture is rugged and adaptable in its configuration.