Topic ID: id_23554165
Version: 2.0
Date: Sep 26, 2020 10:13:49 PM

Gantry Front Cover Removal and Re-Install

Prerequisites

Table 2. Safety

caution

Shock Hazard
Voltage Present
No service on left side while energized.

notice

Potential for front and rear cover damage. Front and rear cover removal and installation can be safely accomplished by (1) person using the dollies provided with the system. Failure to use these dollies will significantly increase the likelihood of damage to the covers. Do not lean covers against walls.

note:

Before beginning this procedure, please read the safety information in Equipment Service - Gantry.

Overview

This procedure explains how to remove and re-install the CT Gantry front cover.

1 Redesigned Front Cover Dolly Setup

Procedure

danger

EQUIPMENT TIP HAZARD
Do not use dollies on uneven surfaces such as steps or elevator thresholds. The dollies are designed to be used on flat level floors within the scanning suite only. Misuse can result in personal injury or damage to covers or other facility items.
ONLY USE DOLLIES ON FLAT SURFACES.

notice

Limited access systems must use redesigned front cover dollies (P/N 5179183) only.

Bring Dolly out of storage into open space. See Figure 1.

Figure 1. Front Cover Dolly in Storage Mode
Pull feet out to form cross. See Figure 2.

note:
One side of the lower foot is shorter than the other to accommodate the wall in small rooms.

Figure 2. Front Cover Dolly Base Assembly
Place the pin to secure the feet into position. See Figure 3.

Figure 3. Place Pin to Secure Feet
Remove the pin from the cover bracket tube. See Figure 4.

Figure 4. Remove Pin from Tube

warning

EQUIPMENT TIP HAZARD
COVER DOLLIES MAY TIP OVER IF NOT CONFIGURED PROPERLY.
ENSURE that all SCREWS ARE TIGHTENED SECURELY AND THE LEGS ARE secured TIGHTLY BETWEEN THE BASE TOP AND BOTTOM PLATES. FAILURE TO DO SO WILL RESULT IN INSTABILITY DURING FRONT COVER HANDLING.

Raise the bracket to the proper height and secure it by inserting the pin into the upper hole on the support tube. See Figure 5.

Figure 5. Secure Bracket with Pin
Position dolly so the pivot bolt for the feet is on the table side (front side) of the gantry. See Figure 6.

Figure 6. Dolly Feet Configuration

note:
The short part of the feet faces outwards toward the wall. The L and R stickers (see Figure 7) refer to the sides as you face the gantry from the front.

Figure 7. Direction Stickers
Once the studs are secured on the cover, tighten the ratcheting handle (see Figure 8).The handle can be pulled out and turned to clear the support tube.

Figure 8. Ratcheting Handle Button
Turn the handle to HAND TIGHT.
Reverse the above steps to disassemble.

2 Cover Removal

Procedure

Position the table at its lowest position.

notice

Always turn OFF the HVDC before the 120 VAC. Turning OFF 120 VAC power before HVDC power can result in equipment damage.

Remove gantry side and top covers, if you have not already done so.
Verify that the three (3) power switches have been turned OFFFigure 9.

Figure 9. Service Switch Panel
Detach front cover J3 and J2 and front cover BKHD J1 cables.
Remove the Mylar (scan) window.
Remove front cover.
1. Disengage upper and lower cantrell brackets on both sides of the cover.
  1. Using steady but firm pressure, lift each of the lower cantrell brackets from their associated retainers. See Figure 10.
    
    Figure 10. Releasing Cover Brackets
  2. Disengage the locking mechanism on the upper cantrell brackets by using your thumb to slide the trigger (red lever) back. This will release the locking mechanism and allow the cantrell to be rotated upwards with steady and firm pressure.
2. Disengage the rubber retaining straps on both sides. See Figure 11. You may find it helpful to lift “up” on the cover to align the stud while attaching the rubber retaining straps.
  
  Figure 11. Rubber Retaining Straps and Cover Locking Mechanism
3. Lift and rotate cover locking arm to unlocked position.
Rotate front cover away from gantry.
1. Move front cover away from gantry, leaving space (about 5 feet) between cover and gantry.
2. Pull the locking pin and rotate front cover away from gantry. Place locking pin in one of the side dolly perforations. See Figure 12.
  
  Figure 12. Releasing Front Cover Dolly Hinge
3. Continue cover removal per Figure 13.
  
  Figure 13. Front Cover Removal Sequence
Rotate the cover horizontally and move it back and over the table to a safe location. Once in a safe location, you may over-rotate the cover full vertically but upside down.
Remove the gantry display from the front cover and place it into its service position.
1. The gantry display is held in place with (5) thumb screws. Use a flat-blade screwdriver to remove the Display. See Figure 14.
  
  Figure 14. Gantry Display Removal
2. Place the Display in the bracket on the right side of the gantry. See Figure 15.
  
  Figure 15. Gantry Display Service Mounting Location
3. Disconnect the cabling at the right rear gantry cover. Only (1) cable will connect to the Gantry Display. Connect the cable taken from the rear cover to the display.
Remove one (1) of the cover’s control assemblies, and place it into its service position.
1. Press on each ball stud until the panel is released. See Figure 16. Keep one hand on the control panel at all times to prevent it from dropping to the floor.
  
  Figure 16. Gantry Control Panel Removal
2. Align the ball studs with their associated receivers and snap into place.
  
  Figure 17. Control Panel Service Position
3. Connect cable to terminator located on the cantrell arm. See Figure 18.
  
  note:
  There are 3 cables, each of which is unique. The ribbon cable is not used in the Service configuration. The other 2 cables will only fit in the terminator or the control panel, not both.
  
  Figure 18. Gantry Service Mode Cable Terminator

3 Installation

Procedure

Remove the gantry display and control assembly from their service positions and reattach them to the gantry cover.
1. Disconnect cables from Display and Gantry Control Panels.
2. Install Gantry Display in front cover. Secure the 5 thumbscrews. With a flat-blade screwdriver, gently tighten past finger-tight.
3. Install the gantry control panel, making sure the ball studs are secure within the receivers.
4. Reattach cables.

notice

Potential for front cover damage. When you rotate the gantry back to its vertical position, make sure not to scratch the front cover with the edge of the table cradle.

Rotate gantry back to its vertical position.
Attach the front cover.
1. Align the studs on both sides of the front cover with each associated receiver. Receiver is located on the gantry frame.
  
  Figure 19. Cover Stud and Mounting Bracket Receiver
2. Insert the stud on one side into its associated receiver and attach the rubber retaining straps.Then insert the stud on the other side into its associated receiver and attach its rubber retaining straps.
  
  You may find it helpful to lift "up" on the cover to align the stud while attaching the rubber retaining straps.
Reattach upper and lower cantrell brackets on both sides.
1. Remove upper Cantrell brackets from service position and rotate them into position over their associated retaining pins. See Figure 20 and Figure 21.
  
  Figure 20. Service Position of Upper and Lower Cantrell Brackets.
  
  Figure 21. Cover Retaining Pins (Top and Bottom)
  
  Press down firmly on the bracket and snap it into place. The locking mechanism on each upper bracket should lock the bracket securely into place. Do this on both sides. See Figure 22.
  
  Figure 22. Locking the cover brackets into place.
2. Remove lower cantrell brackets from service position (Figure 20), and rotate them into position over their associated retaining pins. Press down firmly on the bracket and snap it into place. See Figure 22.
Remove dolly, disassemble and store safely away for later use.
Remove dolly, changed the extension pin location on the gantry front cover bracket, See Figure 23. Disassemble and store safety away for later use.

Figure 23. Remove Dolly
Reattach cables to cover.
Re-install the Mylar (scan) window.

4 Finalization

Finalization

Continue with other cover installation procedures as necessary. When AC power is restored to the system, prior to enabling axial drive or HVDC, remember to rotate the gantry by hand to ensure there is no interference between covers and rotating components.
Verify all covers, especially side covers are properly secured
Ensure there is no interference during all tilt range.