The O.J. Adder
The O.J. Adder is a sturdy dial adder for British currency, probably made in about 1960. It has a heavy case of cast iron, presenting a face with four dials angled towards the user. On the right hand side is a holder containing a plastic stylus.
The rightmost dial is a disc with 12 holes and registers the pence amount. It has 12 holes near the rim labelled 0 to 11, and to add some number of pennies you put the stylus in the appropriate hole and turn the dial until the stylus hits a metal stopping par at the bottom. The total pence amount can be read through another hole inside the dial. If the dial completes a revolution, the next dial is automatically moved one step. That next dial registers shillings, and has 20 holes labelled 0 to 19. The dial to the left of that counts pounds, and also has 20 holes. The last dial is a simple pointer, that counts up to 1000 pounds in multiples of 20.
There is no clearing mechanism. Each disc dial has an arrow pointing to one hole. To reset the dials go from right to left, adding the amount indicated by the arrows. Finally twist the left pointer to zero by hand.
The adder does not have a serial number. The adder has a stored energy carry mechanism. As a dial turns, pins push up a lever against a spring, and then lets the lever drop down again. That lever has a pawl attached so that when it drops the next wheel is shifted one step.
I do not have the original instruction leaflet, but I found photos online and the text is as follows:
The essence of the O. J.
Adder is that good results
are obtained from the ﬁrst,
although practice naturally
increases the operator's
finally turn the knob of the
POUNDS POINTER clockwise
until the pointer points
to 0. The machine is now
ready for use.|
This order of dialling is only necessary for setting the machine to zero. When adding, the dials can be used in any convenient order.
1 12 6 2 7 3 19 18 4 1 10 9 -------- £25 8 10 ---------
After adding these ﬁgures, it will be seen that the POUNDS POINTER indi- cates £20, the POUNDS DIAL shows £5, the SHILLINGS DIAL 8/- and the PENCE DIAL 10d.
Some users prefer to add
each line separately, while
others prefer to add in
columns, either from left to
right, or from right to left.|
Except when setting to zero, it does not matter in what order the dials are used.
At the beginning of an addition, always see that the machine shows zero throughout.
Please see over for Guarantee.
THE OJ. ADDER
Should any defect of material or
workmanship become apparent
within six months of the date of
purchase, we undertake to make
good the defect at our own expense,
and refund the postage, provided
that the machine is returned to us
postage paid, and securely packed
in the box supplied with the
HOLMAN ENGINEERING WORKS
Here is a video where I demonstrate the O.J. Adder.
The O.J. Adder was invented by Oscar Styles Penn (1890-1961). As a young man he had an interest in aviaton and was involved in building and testing the Newington monoplane in Hull. In the first world war he enlisted, joining the Motor Machine Gun Service, and rose to the rank of captain. After the war, he worked at Roadless Traction Ltd. This company was founded in 1919 by Colonel Phillip Henry Johnson, and a few other army officers including Penn. Johnson worked on the development of the military tank in what became the Tank Corps, but I have not been able to confirm whether Penn and the other officers worked there together, but it seems likely. Johnson had been allowed to keep patents on his work in caterpillar tracks, and the company was to commercially develop that.
By 1943 Oscar Penn worked at Aveling-Barford in Grantham, becoming their chief engineer. Amongst many other things, he developed the "calfdozer", a very small bulldozer. After he retired, he lived in Callow Hill, near Kidderminster, where he continued inventing and set up Penn Inventions Ltd in 1955 to commercialize them.
Penn submitted a patent application for the O.J. Adder in 1958. The first adders were made in Holman Engineering Works on Holman Street in Kidderminster, and had a badge on the back that said so. On the back of my machine the badge says the company name O.J. Sales, Anchor Works, Stourport-on-Severn. This town is also next to Kidderminster. It is unclear if my adder was made there or at Holman's. The patent was granted in October 1961, just two months before Oscar Penn died. I have not been able to find any adverts for the adder, so I don't now exactly when it was commercially available, but it must have been inside the period from 1958 and 1961 since all adders have Patent Pending on them.
Oscar Styles Penn has a large number of patents with Roadless Traction related to caterpillar tracks, one for a valve for inflatable liferafts (GB 535,467) which went to the Walter Kidde Company Ltd., and many with Aveling Barford related to machines used in construction such as the calfdozer (GB 575,334). After the adder he patented a rise chair for the elderly (GB 949,995).
|Patent||Filing date||Publish date||Name||Description|
|GB 880,608||27-11-1958||25-10-1961||Oscar Styles Penn Penn Inventions Ltd||Adding Machine|
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