What is this piece of Machinery feature on "Bones"?

I saw it in an episode of bones that took place between Oklahoma and Texas, I assume it's related to oil drilling? What is the gadget called? What does it do? Thanks for your help!
The join is a screen capture of the raise objections, the image is hosted on photobucket and it's clean: http://i10.photobucket.com/albums/a112/fallandhitthepavement/screen-capture-3.png
"> Its a pump. It could be any for oil or groundwater.

http://en.wikipedia.org/wiki/Pump_jack

Related Questions:
How long would it filch a cultivator to acquire crops contained by a 1 mile radius next to out machinery?   Electrical shock trauma injuries from electro-static machinery? see below for more info.?   What tools & machinery are required to refinish wood floors? Also, what is the cost to rent/buy these tools?   Gain on sale of machinery would be record as what? Debit or Credit?   Factory machinery surrounded by the 1800s?plz answer speedily!?  
  • What are the methods to depreciate machineries ?
  • Why does it enunciate "do not use formerly work near heavily built machinery" on the support of childrens Tylenol?
  • Mennonite Farm Machinery?
  • Why does it right to be heard do not use formerly work next to sweet machinery on the put a bet on of childrens tylenol?
  • How do bubble bearing exhaust friction within machinery?