How does a mechanical watchman clock system work?
 

Mechanical watchman clocks:
How do these things work in the most basic set up?

You have a few basic components:
1) The watchman clock itself, with a carrying strap or belt clip.
2) A report tape, or a report disk.
3) Guard stations, guard tour stations, or checkpoints.  All the same, different watchman clock manufacturers call them different names.  We like to use the term "checkpoints" as you check those points, or those stations. 

First, you need to know how many stations or checkpoints you will need.  Let's say you have a mall to check.  In this mall are 4 main doors, 4 entry points, and 4 public rest rooms.  That gives you a total of 12 checkpoints.  

All mechanical watchman clocks have some way of telling you roughly what the date is and what the time is when the guard gets a reading from the checkpoint.  Dial clocks - made by Acroprint -  are somewhat inaccurate, as you do not know exactly (to the minute) when they went to that checkpoint. 

Another drawback is that you usually have to change the dial on a daily basis, and this is a lot of work, and a lot of disks to keep track of.  They are Pie Charts, they look like the faces of a dart board.  In this category are the Acroprint clocks and the Detex Newmans.
Tape clocks, such as the Amano PR600 and the Detex 24 or Detex Guardsman are the easiest to read.  Plus, most tapes last for over 1000 registrations, or a minimum of 2 weeks before requiring replacing.  If you have the choice, get a tape system and avoid dials or disks.

Each checkpoint gets either a letter (A,B,C,D,E) and so-on, or a number (1,2,3,4,5,6,7,8 and on and on).   You make a note as to what letter is which location.

So this is what happens when the guard does his job.  "ED" the guard, grabs the watchman clock.  He checks the time on the face and is pretty certain it is working. 
Ed leaves the guard house or the office, and proceeds to whichever station you deem as the first for his round.  At that checkpoint, Ed locates the dull gray box and removes the metal station key.  The key is typically connected by a steel 2 foot chain.  

Ed inserts the key into the watchman clock, then gives it a twist to the right.  It then embosses the paper, leaving a record of the time, date, and checkpoint that he was at.  Ed does this again at the next station, and the next, and the next.

When it's over, Ed leaves the watchman clock in the office, and punches out.  Jack, Ed's supervisor, uses a special case key and opens the machine.  Whenever the case is opened, a mark is made on the report record.  Jack then either puts the tape in to a box in his desk, or more likely, throws the report tape or disk away (that's reality).  In a perfect world, Jack would read the tape to see if Ed did his job.  Jack would then store the tape and write on it the date that he read it.   Jack, being a sharp guy, would also notice if Ed took too long between checkpoints, or if he missed one.   Jack would also replace the battery, or wind up the spring, depending on the watchman clock model.  

Computerized watchman clocks are completely different, much more versatile, and also simple to use.