🚀 go-pugleaf

We touched on this in the past.

Has anyone ever used one or seen them in operation?

These were, in a sense, giant adding machines that could post
a transaction on multiple documents simultaneously, e.g. a
journal, ledger card, and customer receipt, and keep multiple
totals.

My employer used one for specialized accounting work
that would not fit on the computerized accounting system.

It appears that while they required multiple entries and
didn't store anything (for the most part), they were very
popular and cheaper than punched card machines despite the
extra labor needed to operate them (I guess clerks were
still cheap in the 1950s and 1960s).

That is, when doing a payroll, the clerk had to enter the
wage-rate and year-to-date totals for each employee in each
pay period, rather than the machine keeping it stored on a
punched card replaced each cycle.

I think that had metal bars that could be notched to 
facilitate the process.

In later years, they could get connected to electronics to do
more calculations.

Bitsavers has some interesting material under Burroughs and NCR.
The patent information is tough to read, but has some operating
details of the older machines.

Below are two typical ads for them:

http://blog.modernmechanix.com/national-accounting-machines-save-us-17000-a-year-repay-their-cost-every-10-months/

http://blog.modernmechanix.com/these-burroughs-sensimatic-savings-can-be-yours/