Adding-Machine Page: 5 of 6
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405,924
wheel to cause the hands on the dials to move.
The mode of operating this portion of the
mechanism is as follows:
At a point below the universal bar, and se-
5 cured to the upright G, is a flat spring H, the
lower portion of which is cut out to form a
longitudinal slot h, in which a portion of the
periphery of the ratchet-wheel moves. This
springis constructed with two ears h1, by which
io it is secured to the upright, and the lower por-
tion is bent out, as shown at h1, at a point
where the slot terminates, so as to form a face
for engaging the teeth on the ratchet-wheel.
The upper end of this spring forms a shoul-
15 der 1h', against which rests a spring hL", se-
cured to the upright and bearing upon the
said shoulder, thereby causing it to engage
the teeth on the ratchet-wheel. The upper
end of this upright extends up, as shown, and
20o works between the guides formed by the two
upright pieces g g'. At a point near the top
of the upright G is secured a coiled spring I,
rigidly attached at its lower end to the top of
the casing A, as shown at a'. Now it will be
25 seen that when one of the keys e is pressed
down the end of the shank e' bears against
the universal bar F and raises it, and with it
the spring i1, the distance that the wheel is
turned being equivalent to the number on
30 the key; or, in other words, if the keyis num-
bered 4, the distance that the wheel will re-
volve will be equivalent to the distance be-
tween four of the teeth. As soon as the key
is released, the spring I draws the universal
35 bar F back into position, and with it the key.
It will be observed that these guides g' tilt
inward. The object for constructing them in
this manner is that when the keys are raised
the under surface of the universal bar FI will
40 be prevented from slipping, and thus gener-
ating a certain amount of friction, which
would be the case should the upright work
vertically. If desired, this guide may move
in the are of a circle, so that the end of the
45 shank, instead of slipping when the universal
bar reaches a certain point, will be allowed
to rock thereon, and thus prevent undue fric-
tion.
It is desirous to so arrange the keys that
50 the length of their stroke will be just suffi-
cient to cause the hand or pointer to revolve
just the number of figures that the key is
marked. In order to accomplish this, the fol-
lowing mechanism is employed:
55 To the rear portion ac of the easing are se-
cured a number of stops J, in the sides, pref-
erably, of which are cut recesses j of unequal
length, the slot which the shank of the key
numbered 1 engages being shortest, and
60 the one that the shank of the key numbered
9 engages being the longest. At the upper
and lower ends of these stops are cut lon-
gitudinal slots j', through which pass screws
fj, for holding the said stops in proper posi-
65 tion within the easing. Thus when the key
is pressed down the distance between the up-
per and lower faces jff on the recesses willbe equivalent to the distance between the
number of teeth on the wheel corresponding
to the key that is pressed down. Now in ad- 70
justing this device should it be found that
when the key is struck it will carry the hand
or pointer either too far past the given figure
or not quite to it, the stroke of the key may
be adjusted to a nicety by simply loosening 75
the screws f and moving the stops either up
or down.
It has been found in practice that should
the operator strike the key a sharp blow the
universal bar will be thrown up too far to 80o
allow the hand to register accurately, and in
order to obviate this difficulty an arm K, pro-
vided with a hook k, is secured to each of the
keys, and is inclined slightly forward, so that
when the keys are raised they will move in 85
the are of a circle. Now it will readily be
seen that when the key is pressed and has
reached the end of its upward stroke the
hook K will engage the upper edge of the uni-
versal bar F, and thus prevent it front going 90
farther than is necessary to move the ratchet-
wheel the number of teeth desired; but while
this means is adopted to prevent the univer-
sal bar from going too far, it will be neces-
sary to adopt a certain and effective device 95
for preventing the ratchet -wheel from turn-
ingtoo far independent of the universal bar-
as, for instance, if the shaft on the ratchet-
wheel worked loosely within the bearings and
the key were to be struck a quick and hard 1oo
blow, while the universal bar would be stopped
and prevented going too far, still the ratchet-
wheel from the velocity imparted to it might
pass the given limit. In order to correct this
and effectively guard against such an acc, 105
dent, a stopping device is secured within the
casing and above the keys, and is so arranged
that when the key has reached the limit
of its upper stroke a pawl will engage the
teeth on the ratchet-wheel and at the same o10
instant that the spring IH ceases to operate.
In order to accomplish this result, I pivot a
lever L within the casing, the trunnions / of
which rest in suitable bearings in the casing.
(See Fig. 6.) This lever may be made in any I15
shape; but that shown in the drawings is pre-
ferred on account of its lightness and sim-
plicity of manufacture-thlat is, made in the
form of an oblong frame having on one side
an arm 1', provided at its end with a pawl l', i20
designed to engage the teeth on the ratchet-
wheel. To each of the keys e is secured an
upright e2, designed to strike against the real
portion of the lever L when the key is pressed
down, and thus force the pawl 1' down into 125
the teeth on the ratchet-wheel. These arms
e vary in length and are tile reverse of the
recesses j--that is, tlle arm i on the key
marked 1 being the longest and the one on
the key marked 9 being the shortest, for the 130
reason that the first-named key only has to
travel one-ninth the distance of the last-namned
key in performing its function. Consequently
if the arm were not longer the ratchet-wheel
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Stinson, James C. Adding-Machine, patent, June 25, 1889; [Washington D.C.]. (https://texashistory.unt.edu/ark:/67531/metapth172083/m1/5/: accessed June 24, 2024), University of North Texas Libraries, The Portal to Texas History, https://texashistory.unt.edu.; crediting UNT Libraries Government Documents Department.