Module - Gearing Installation & Maintenance Flashcards
What is the name of the organization that develops guidelines and standards for gears in North America?
American Gear Manufacturers Association
You have been given a work order asking you to work on a small gear train. What should you do first regarding immobilizing the machine?
isolate and lock out the machine
Why is it impossible to shut some gear drives down for maintenance?
Damage from heat may occur.
If someone asks you to remove safety guards while the machine is running, what should you recommend?
Safety guards should never be removed while units are running.
What are two common methods of lubricating open gear sets?
by drop and force-feed systems
How can you check the backlash in a large open gear set (with the unit shutdown)?
by placing the largest feeler gauge that will fit between the mating gears
What symptoms appear when a gear set is adjusted with less than minimum backlash?
The gears give off a loud whining sound.
How does potential energy stored in a shut down machine pose a threat to the person assigned to work on the machine’s main input gear reducers?
The output coupling may be under torsion forces that could entangle the worker when the coupling is mechanically disconnected.
What safety precaution should be taken before disconnecting a chain drive from a gear reducer to a loaded bucket elevator?
Contact the operator and have the elevator unloaded before locking it out.
How are shaft-mounted reducers fastened to the shafts they drive?
by keys and set screws
Why should you use a torque arm on a shaft-mounted reducer?
to prevent gearbox rotation
Some shaft-mounted reducers use a device to absorb torsion load shock. What device do gearbox manufacturers use to do this?
spring type torque arms
What is the proper positioning for the torque arm installed with a shaft-mounted reducer?
Install the torque arm 90° from a line running from the output shaft to the point of attachment.
How can you make slight speed ratio changes on shaft-mounted speed reducer drives?
Change the motor drive sheave or reducer input sheave size
Why are match marks placed on gearboxes?
for ease of reassembly
What should be done to the top cover of a gearbox to make the cover break free of the bottom?
Drill and tap the top cover flange and install jacking bolts.
Why do you not use hardened steel wedges between the split joint of a gearbox for removal purposes?
You may damage or break the cover.
Why should you give a close inspection to the inside of the top cover?
Inspection can reveal problems, such as contamination.