Improvements in and relating to Typewriting Machines.
Year: 1899

page_text: Date of Application, 3rd Oct., 1899-Accepted, 6th Jan,, 1900
COMPLETE SPECIFICATION.
Improvements in and relating to Typewriting Machines.
We, ROBERT TURNER, of 1134, 25th Street, Des Moines, Iowa, United States
of America, Mechanical Engineer, and DUPLEX TYPEWRITER COMPANY, a Corpora-
tion organized under the Laws of the State of Iowa, located at Des Moines, Iowa,
United States of America, Manufacturers, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:
Our invention relates to typewriting machines, and particularly to the
action thereof," whereby the impression blows are struck.
Our object is to produce an improved action embodying vertically guided
finger-keys, vertically movable key-levers, adapted to slide longitudinally,
auxiliary bell-crank levers, connected to and vertically actuated by said key-
levers, type-bars suitably mounted, and draw-bars connecting them to said
auxiliaries.
The auxiliaries are mounted, in alternation, upon suitable parallel supports,
below the key-levers, and one arm of each is suitably connected to a spring,
upon which tension is produced, or increased, when a key-lever is depressed,
whereby said spring aids in both returning the several parts to their normal
positions, and there retaining them.
It is constructed as follows, reference being had to the accompanying draw-
ings, in which,
Fig. 1, is a vertical sectional detail of a typewriting machine, showing sufficient
of the working parts to illustrate this invention.
Fig. 2, is a top plan, (partly in section), on line A A, Fig. 1, of a few of the
auxiliary bell-crank levers and their mounting in alternation.
Fig. 3, is a vertical sectional detail on line B B Fig. 1, illustrating their
mounting.
Fig. 4, is a vertical sectional detail of a key-lever, a bell-crank, a connection
between them, and a draw-bar, as upon line C C in Fig. 1.
Fig. 5, is a detail, in side elevation, enlarged, of a slot and pin joint or
connection between the key-lever, and the stem of the finger-key.
Fig. 6, is a vertical section thereof.
Fig. 7, is a detail in side elevation, enlarged, of a slot connection between
said parts.
Fig. 8, is a vertical section thereof.
a is a suitable frame for a typewriting machine, having a suitable type-bar-
ring b in which suitable type-bars c are journaled, here indicated as concentric
to the printing point upon the impression platen d, and e is a suitable basket-ring.
Upon the base of the frame, parallel bars f g are erected, each having a
longitudinal groove h, and vertical transverse notches, intersecting said grooves,
which receive the tail pieces of the bell-cranks j, their trunnions k fitting in
said grooves à forming a hinge, or pivot bearing, for each bell-crank; said
cranks being arranged in alternation as shown in Fig. 2.

page_text: Suitable draw-bars 7 connect said bell-cranks to said type-bars.
Suitable springs m connect the short arms of each pair of bell-cranks, whereby
each spring controls two type-bars, to normally hold their short arms against
suitable stops n, or against the basket-ring, but will permit either type-bar to
be operated.
Suitable finger-keys o are mounted in the frame, their stems, passing through
guide-bars across the frame, and the shank of each is suitably connected to
a key-lever g, as by any ordinary slot and pin joint (Figs. 5 and 6), or by any
ordinary slot connection w. The rear end of each key-lever is provided with
an adjusting screw which has a bearing, frictionally, against the cross-bar s,
and is free to slide more or less thereon, when the lever is operated.
A link connects each key-lever to a bell-crank.
•
Cross-bars operate as stops to the upward movements of the key-levers, and
can be provided with a suitable cushion to reduce the noise of operation.
It will thus be seen that the bell-cranks are spring connected in pairs, whereby
the tension of the spring is exerted both ways against separate cranks, so that
cach does double work.
It will also be evident that the bell-crank can hook over and swing upon a 1od
common to all of them in each set, instead of using trunnions.
The key-levers are thus, respectively, under equal spring tension, requiring
the equal force of stroke to depress a finger-key, its stem, its key-lever, its bell-
crank to which it is link connected, and the corresponding draw-bar to impel
the proper type-bar to make an impression.
The bell-cranks are arranged in two sets, the bearing common to each set
is parallel to that of the other set, the links of each set are equidistant from
the bearing, and equidistant from the fulcrum of each key-lever, and the draw-
bars connected to the bell-cranks are at the ends of the long arms of the bell-
cranks, and equidistant from the links and lever fulcrums, and the lever fulcrums
are arranged in sets corresponding to the bell-crank bearings; all of which
results in an absolute uniformity of action and evenness of force of stroke to
operate each type-bar.
These are a part of the advantages or purposes of the auxiliary or bell-crank
levers beneath and connected to the key-levers, the spring tension being exerted
directly upon the bell-cranks and through the links upon the key-levers, draw-
bars and type-bar arms, or levers; whereby each single spring supplies tension
to two key-levers.
It will be evident that each pair of the screws r by being adjusted will produce
the same tension upon each spring m and each pair of key-levers, and that by
using some device of the nature of a dynamometer the tension of the several pairs
can be made the same, so that the force to operate any key will be the same
as that for any other key.
Each screw operated upon one end of each spring through the key-lever, link
and bell-crank, and in case there is any slight variation in any spring, either
in length or strength, the screws can make the tension of all of the springs the
same, by regulating the distance of the rear end of each key-lever from the
plate s.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is :—
1. In a typewriting machine, the combination with a pair of key-levers, of a
pair of bell-cranks arranged in alternation, and links connecting their long arms
respectively, to said key-levers, of a spring connecting the short arms of said
cranks and exerting its tension upon both of said cranks and levers, and type-
bars suitably connected to said bell-cranks.
2. In a typewriting machine, the combination with the key-levers, of auxiliary
bell-crank levers connected to them, and springs coupling said bell-cranks in

page_text: pairs, whereby each spring exerts its force upon two key-levers and type-bars
suitably connected to said bell-cranks.
3. In a typewriting machine, an action comprising key-levers, auxiliary bell-
crank levers connected thereto, type-bars connected to said bell-cranks, and
springs coupling said bell-cranks in pairs, whereby each spring does double
work in returning the other members of the action to their normal positions.
4. In a typewriting machine, an action comprising key-levers, auxiliary bell-
crank levers connected thereto, type-bars connected to said bell-cranks, and
springs coupling said bell-cranks in pairs, whereby each spring does double
work in returning the other members of the action to their normal positions,
and stops against which said type-bars are normally held by said springs.
5. In a typewriting machine, an action comprising longitudinally sliding and
vertically oscillating key-levers, auxiliary bell-crank-levers, connected thereto,
type-bars connected to said bell-cranks, and springs coupling said bell-cranks in
pairs, and exerting their forces to lift and slide each key-lever separately and
to separately return each type-bar to its normal position, and means to adjust
the rear bearing of each key-lever and regulate the tension of said springs.
7. In a typewriting machine, a main frame, parallel longitudinally grooved and
transversely notched bars erected thereon, bell-cranks pivoted upon said cranks
in alternation, and springs coupling said bell-cranks in pairs, combined with
key-levers and type-bars separately connected to said bell-cranks.
Dated this 3rd day of October 1800
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicants.