Pistol Grip Tool (PGT) Flashcards
1
Q
NASA-EVA Pistol Grip Tool (PGT)
A
Purpose: This tool is designed for use by astronauts during EVA to apply torque to the Hubble Space Telescope and International Space Station mechanical interfaces and fasteners.
2
Q
PGTs are some of the most commonly used EVA tools and are used for almost all bolt-driving operations.
A
Description:
- The PGT is a self-contained, microprocessor controlled, battery powered, 3/8-inch drive handheld tool and non-powered ratchet wrench.
- There are numerous torque, speed, and turn/angle limits that can be programmed into the PGT for use during various mission phases.
3
Q
PGT COMPONENTS
A
- ON/OFF SWITCH
- MODE SWITCH
- SPEED COLLAR
- TORQUE COLLAR
- RATCHET COLLAR
- MULTI-SETTING TORQUE LIMITER (MTL)
- TRIGGER
- RS422 PORT
- SOFT TETHER POINTS
- BAYONET FITTING
- PGT BATTERY
4
Q
PGT IDENTIFICATION (S/N#)
A
- PGTs are identified by large ID numbers stenciled in the thermal tape on the side and top of the chassis, instead of serial numbers.
- The ID numbers represent the last digit of the serial number. Therefore, PGT s/n 1001 to 1008 have ID numbers of “1” to “8”.
5
Q
- ON/OFF SWITCH
- MODE SWITCH
A
- On the back of the PGT body, above the On/Off Switch, is a switch to toggle the PGT torque mode. This works in conjunction with the Torque Collar. The torque collar has seven settings.
- The Mode Switch allows for seven settings in “A” mode and seven additional settings in “B” mode (A1-A7, B1-B7). When operating this switch using the EMU glove it is easy to either inadvertently toggle the On/Off switch or miss the Mode switch entirely.
6
Q
SPEED COLLAR
A
- The Speed Collar is the aft-most collar on the PGT body. This collar controls the rotational speed of the PGT output shaft and also provides a setting to perform the calibration procedure. See Calibration.
- The Output Shaft rotates in the clockwise direction for CW settings and counter-clockwise for CCW settings. All speeds are in Revolutions per Minute (RPM). All six (CW1-CW3 & CCW1-CCW3) speed settings are independently programmable. Speeds can be programmed between 5-60 RPM. In practice the CW and CCW speeds are programmed the same.
7
Q
ALPHANUMERIC DISPLAY
A
The PGT alphanumeric display provides the torque and speed setting, actual torque achieved, turn count, and fault messages. Contents of the display depend on the PGT mode/settings and are software controlled. Decimal values are distinguished by a smaller font. The display will go blank if the PGT exceeds the programmed auto-sleep time.
