Westclox is an American company, which focused in development and producing easy, cheap but efficient watch movements. One of those was also it's alarm W5 movement. It's quite obvious, that development of this movement and watch was heavily influenced by Junghans,so case, dial and some parts of the movements are from Jungahans. It is quite possible that entire movement was developed by Jungans and that only due to the custom regulations it was assembled in USA.

Movement W5 has a joint spring barrel for time and alarm, it has no jewels at all. Watch with working movement is therefore very hard to find nowadays, since nobody expect this movement to be serviced at all.  

Instruction manual:

Central crown in position 0: Winding.

Central crown in position 1: Setting the time.

Button above 2.00: by pushing the button alarm hand moves 10 minutes backwards.

Side button at the left side of the case: Up - alarm On; Down - Alarm Off