glad hand

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Informal A warm and hearty, but often insincere welcome or greeting.
• noun A coupling device used to connect air hoses between rail cars or between a tractor and trailer.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A warm welcome offered a guest by a host.
• noun A coupling device used on semi-trailer trucks for attaching air brake lines from the tractor to the trailer.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a warm welcome; may be insincere