PROVEMENTS IN CALCULATING MACHINES."
Year: 1878

page_text: PROVISIONAL, SPECIFICATION left by Henry Porter at the Office of the
Commissioners of Patents on the 25th January 1878.
HENRY PORTER, junior, of Stockton-on-Tees, in the County of Durham.
PROVEMENTS IN CALCULATING MACHINES."
Iм-
The object of my Invention is to provide a simple and efficient machine specially
adapted for calculating wages, but capable of being used as a ready reckoner
generally for calculating rates of interest, prices of goods, and the like purposes.
I will describe my Invention specially as applied. to machines for calculating
workmen's wages.
According to one arrangement I provide an outer cylinder or casing secured to a
suitable box or bed; this cylinder has a slot way cut lengthwise in same, and on one
or both sides of the aperture of the slot way I mark the hours and half hours and
quarter hours if necessary.
Inside the fixed cylinder aforesaid I provide another cylinder with slot way like
that in the fixed cylinder and of or about the same size thereof, and on or to this
cylinder I attach a pounds, shillings and pence table; this cylinder is provided with
boss at bottom passing through the base plate, and to the boss a pinion is securely
keyed; the said pinion is in gear with an internal toothed wheel, which latter is
provided with a handle or arm.
There is another and inner cylinder mounted on a spindle at bottom passing
through the boss on which the other cylinder is mounted and resting on cross bar
of the base. This spindle also carries a pinion actuated by internal segmental
wheel similar to that into which the other pinion gears, and this wheel is also
provided with a handle or arm as in the previous case.
.
There may be additional cylinders if required, all constructed and acting
substantially in the same manner; these might be necessary where complicated
calculations or large number of rates had to be calculated. To the inner cylinder
the pounds, shillings, and pence table is also affixed, and when at work the arms of
these cylinders may be brought over one another, and thus bringing the slot ways
on the two cylinders even or opposite one another,

page_text: The arms on the segmental wheels pass through slots formed in the base, and on
the edges of the slots the rates per week are placed.
The operation is as follows:-Supposing it is required to find the value of fifty-
four hours at eighteen shillings per week, set one of the arms at three shillings per
day, when opposite fifty-four hours will be found indicated eighteen shillings, the
sum required. Again, suppose the value to be sixty hours at thirty-six shillings
per week, bring one (the upper) arm to the end of slot and the other to thirty-six,
and opposite sixty the required sum is found.
According to another arrangement, I fit the casing with only one inner cylinder,
in which case the number of rates will be reduced, and one segmental wheel will
be sufficient; also by dispensing with the half hours between each hour on the
stationary board the space will be reduced by one half, therefore one cylinder will
act in place of two; in all cases the 1/4, 1/2, or 3/4, will be at the top, so that it can be
added to the total. By this latter arrangement the cost of the machine is
considerably reduced.