1) A Johnson Bar, aka "J"-bar, is a lever-dolly; (a wheeled prybar having an extended handle and a deep reverse-beveled nose-iron), which is used to jockey heavy apparatus into position.
2) A hand lever with several distinct positions and a positive clutch to hold the lever in the selected position. The positive clutch is typically activated with a spring-loaded squeeze handle on the lever so that only one hand is needed to release the clutch, move the lever, then reengage the clutch.
3) Sometimes used in a sexual context since a 'j bar' looks like...you know.
4) If used would be considered an archaic term except you can still purchase them in tool catalogs.
guy: It's is really hard when you have a name like 'Willie', 'John', 'Crapper', or 'Quisling'. Everyone makes a big joke out of it. Kind of like being a 'Li' from China or 'Smith' from the US. However, Archimedes said, "Give me a big enough lever, and I will move the world."
The US census says that the 20 most common names are: Smith 1.01%, Johnson 0.81%, Williams 0.70%, Jones 0.62%, Brown 0.62%, Davis 0.48%, Miller 0.42%, Wilson 0.34%, Moore 0.31%, 0. Taylor 0.31%, Anderson 0.31%, Thomas 0.31%, Jackson 0.31%, White 0.28%, Harris 0.28, Martin 0.27%, Thompson 0.27%, Garcia 0.25%, Martinez 0.23%, Robinson 0.23%, Clark 0.23%, Rodriguez 0.23%, Lewis 0.23%, Lee 0.22%, Walker 0.22% Hall 0.20%, Allen 0.20%, Young 0.19%, Hernandez 0.19%, and King 0.19%
girl: Damn, I know what you mean my name is Taylor Willamina Martinez-Johnson.