1. SLAC RC Status Report US LHC Accelerator Research Program
BNL - FNAL- LBNL - SLAC
SLAC RC Status Report
20 September 2010
LHC Collimation Working Group Meeting
Tom Markiewicz/SLAC

2. Reminder: Last Slide from 30-August-2010
With 4 of 7 rolled pins replaced with solid stainless pins, the clamp, thrust bearings, stainless bearings
Pawl fails at 150 inch-pounds torque
Rolled pin holding first bevel gear shears at 204 inch-pounds
Immediate plan: improve L drive unit
Replace rolled pins on ratchet axle with solid stainless
Replace pawl with a more classic design where a radial spring causes a “dog” to engage ratchet tooth
Test unit to ~400 inch-pounds
Then implement these changes on R unit and test it
Then final assembly & welding & testing & alignment in clean-room using ion-deposited W-S2 parts . Then bake out & ship.
LHC CWG September 2010
RC Status - T. Markiewicz

3. 01-September: Geneva Drive Axle Breaks at ~300 inch-pounds of torque
LHC CWG September 2010
RC Status - T. Markiewicz

4. Drive Rebuilt: tested 16 Sept → >440 inch-pounds
Add Large Thrust Bearing at end of Axle to prevent bending
Exchange Geneva Drive for Pair of 1:1 Gears (load reduced x3)
5mm Moly shaft (& two bearing sets) -> 6mm Steel (& larger bearing sets)
LHC CWG September 2010
RC Status - T. Markiewicz

5. RC Status - T. Markiewicz
Safety Factor
30 in-# to bend each ~1m tube 360 degrees
40 in-# to rotate jaw on moly split ring 1mm ceramic ball support
100 in-# total in this configuration
LHC CWG September 2010
RC Status - T. Markiewicz

6. RC Status - T. Markiewicz
Next Steps
Switch out primary support bearing for 20mm/42mm Steel
Anticipate friction torque will go to ~ zero and increase safety factor
Mount new “pawl”
Decide on Geneva vs. gear
Decide on Steel vs. Ceramic main bearing
Assemble, weld, test & ship
LHC CWG September 2010
RC Status - T. Markiewicz