NSN 6645-00-572-2451 — Detex Newman Watchman Clock

The Detex Newman® Watchman Clock, identified under NSN 6645-00-572-2451, is a mechanical guard tour device historically used to verify security patrol activity. The Newman was the first portable watchclock designed and manufactured in the United States and became widely recognized for its rugged construction and dependable operation.

Purpose and Operation

The Newman Watchman Clock was designed to document that a security officer visited designated checkpoints at required intervals. At each station, the officer inserted a uniquely coded key into the clock and turned it. This action produced an embossed impression on a preprinted paper dial inside the unit.

The embossing recorded both the station number and the exact time of the visit. Because the system used mechanical embossing rather than ink, it avoided messy ribbons or carbon forms and created a permanent, tamper-resistant record.

Mechanical Construction

The Newman clock featured:

• Solid one-piece metal case construction
• All-metal internal components
• 11-jeweled, spring-wound movement
• Weekly winding requirement

The dial was synchronized with the clock mechanism so that consecutive station registrations appeared as continuous bands. Missed stations showed up as visible gaps, making incomplete tours easy to identify.

Capacity and Security

The Newman system could accommodate up to 40 checkpoints. A built-in tamper detector indicated if the clock case had been opened. Paper dials and recording tapes were difficult to counterfeit, providing reliable documentation.

The Newman was one of the first portable watchclocks to receive Underwriters Laboratories (UL) listing and Factory Mutual approval, and it was accepted by insurance carriers worldwide.

Legacy Status

While the Newman and Guardsman mechanical watchclocks are no longer in production, they remain an important part of guard tour system history. Modern electronic guard tour systems have replaced mechanical embossing units with RFID readers and digital reporting software, but the Newman set the standard for patrol verification reliability.