Rotary table drive rigs

Rotary table drive rigs

Illustration No. 2 shows a picture of a rotary table drive type machine. The basic difference between the rotary table drive and the top-head drive machine is that on the rotary table drive machine the rotation power is applied to a rotary table and through this to a kelly; which is either a square, hexagonal, or fluted-type drill rod that passes through the table and picks up the rotation power from the table as it slides through a mated fitting on the table. The kelly is attached to the drill rod in the same manner as the rotary head is on a top-head drive rig.

Item #1 of Illustration No. 2 is the rotary table. Item #2 is the kelly. Item #3 is the air hose that connects to the top of the kelly to transmit air to the inside of the kelly, and from there to the bit. Item #4 shows a section of the derrick. One of the hydraulic cylinders used to raise the derrick from the horizontal to the vertical, or drilling position, is shown by item #6. Item #5 shows the swivel. This keeps the air hose from turning with the kelly, but still passes air through the kelly without allowing for any leakage.

Item #7 is the air compressor and item #8 is the truck cab. Item #9 is a dust collector and is very important when drilling just with air as a means of moving the cuttings out of the hole.

Even though these two types of machines are different in construction, they still come back to the same basic principle of providing air for drilling, and providing rotation to rotate the drill in the hole. Everything else is accessory to these two main facts.