The next effort in this class of machines is illustrated in a patent
issued to Frank S. Baldwin in 1875 (see illustration on opposite page).
The Baldwin machine is also of moment as having the scheme found in
the machines known as the Brunsviga, made under the Odhner patents--a
foreign invention, later than that of Baldwin, used extensively abroad
and to a limited extent in this country.
The contribution of Baldwin to the Art of recording-calculating devices
seems to be only the roll-paper in ribbon form and the application
of the ink ribbon. The method used by Barbour for type impression
was adapted and used by Baldwin; that is, the hinged platen and its
operation by hand.
Of the illustrations shown of the Baldwin machine, one is reproduced
from the drawings of the patent while the other is a photo reproduction
of the actual machine which was placed on the market, but, as may be
noted, minus the printing or recording device shown in the patent
drawings.
[Sidenote: _Description of Baldwin machine_]
Referring to the photo reproduction, the upper row of figures showing
through the sight apertures in the casing are those of the numeral
wheels which accumulate the totals, and which in the patent drawings
would represent the type of the accumulator wheels for printing the
totals of addition and multiplication or the remainders of subtraction
and division.
[Illustration: From Drawings of Baldwin Patent No. 159,244]
[Illustration: Baldwin Machine]
The figures showing below serve to register multiples of addition and
subtraction which would read as the multiplier in multiplications
or the quotient in division. These wheels are the type wheels N, in
the patent drawings, which serve the purpose of recording the named
functions of calculation.
The means by which the type wheels of the upper row are turned through
the varying degrees of rotation they receive to register the results
of calculation, consists of a crank-driven, revolvable drum, marked E,
which is provided with several denominational series of projectable
gear teeth h, which may be made to protrude through the drum by
operation of the digital setting-knobs g, situated on the outside of
the drum.
These knobs, as shown in the patent drawings, are fast to radial arms,
each of which serves as one of three spokes of a half-wheel device,
operating inside the drum and pivoted on the inner hub of the drum.
These half wheels marked F, in the drawings, by means of their cam
faces h¹, serve to force the gear teeth out through the face of the
drum, or let them recede under the action of their springs as the knobs
g, are operated forward and back in the slots x, of the drum provided
for the purpose.
As will be noted from the photographic reproduction of the machine,
these slots are notched to allow the arms extending through them to
be locked in nine different radial positions, and that each of these
positions are marked progressively from 0 to 9.
This arrangement allows the operator to set up numbers in the different
orders by springing the setting-knobs g to the left and pulling them
forward to the number desired, where it will become locked in the notch
when released. This action will have forced out as many gear teeth
in each order as have been set up by the knobs g in their respective
orders.
The lateral positions of the projectable gear teeth correspond to
the spacing of the type-wheels, and an intermediate gear G, meshing
with each type, or register wheel, is loosely mounted on the shaft H,
interposed between the said wheels and the actuating drum E, so that
when the drum is revolved by the crank provided for that purpose, the
gear teeth protruding from the drum will engage the intermediate gears
G, and turn them and their type or register wheels as many of their ten
points of rotation as have been set up in their respective orders of
the setting devices of the drum.
Revolving the drum in one direction adds, while revolving it in the
opposite direction subtracts, and repeated revolutions in either
direction give respectively the multiple forms of addition or
subtraction which result in either multiplication or division, as the
case may be.
The actuating drum E, is provided with means by which it may be shifted
to the left to furnish means for multiplying by more than one factor
and to simplify the process of division.
The means for the carry of the tens consist of a series of teeth i,
formed by the bent end of a pivoted spring-pressed lever arm which is
pivoted to the inside of the actuating drum with the tooth protruding
through a slot in the drum, so arranged as to allow motion of the tooth
in a direction parallel to the drum axis.
[Illustration]
[Illustration: From Drawings of Pottin Patent No. 312,014]
Normally these teeth are held in a position to escape engagement with
the intermediate gears G, but provision is made for camming the teeth
i, to the left into the path of an intermediate gear of one order as
the type or register wheel of the lower order passes from 9 to 0.
The parts which perform this function are the cam m, located on the
left side of each wheel, the plunger M, which operates in the fixed
shaft H, and which has a T-shaped head that, when projected into the
path of the carrying teeth i, serve to cam them sidewise and bring
about the engagement referred to, which results in the higher type or
numeral wheel being stepped forward one space.
The cam-lugs j on the drum serve to engage and push back the T heads of
the cam plungers M, after they have brought about the one-step movement
of the higher wheel.
[Sidenote: _Baldwin’s printing mechanism_]
The printing device consists of a hand-manipulated frame pivoted to
the main frame of the machine by the shaft t. The paper is supplied
from a roll about the shaft t, and an ink-ribbon is fed back and forth
from the rolls u and u¹ over bars of the printing-frame which protrude
through slots in the casing and act as platens for the impression of
the paper and ink-ribbon against the type.
It is presumed that the paper was torn off after a record was printed
in the same manner as in the more modern machines.