Improvements in or relating to Key Board Mechanism for Typewriters and Analogous Machines.
Year: 1898

page_text: Date of Application, 25th Jan, 1898-Accepted, 9th Apr., 1898
Improvements in or relating to Key Board Mechanism for
Typewriters and Analogous Machines.
A communication from EDMUND B. KIRBY, of 411, 21st Street, in the City of
Denver, County of Arapahoe, State of Colorado, United States of America, Mining
Engineer.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex
Chartered Patent Agent, 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 :—
The present invention relates to certain modifications in the key board mechanism
for type writers and analogous machines, which is described in the application
No. 1979 filed contemporaneously herewith. The objects of the present invention
are to simplify the mechanism and to increase its efficiency and durability.
The invention consists in the construction and combination of parts which are
hereinafter described in detail, and definitely set forth in the claims.
In the drawing Figure 1 is a plan view of the mechanism embodying the invention;
Figure 2 is a sectional side elevation of said mechanism on line 2-2 of Figure 1,
viewed from the right; Figure 3 is a sectional side view on line 3-3 of Figure 1, of
certain parts of the mechanism, viewed from the left; Figure 4 is an enlarged view
of the mechanism for holding and releasing the striking bar; Figure 5 is a similar
view of the saine parts when in position to release said striking bar; and Figure 6 is
a front view of some of said mechanism.
Referring to the parts by letters, a, 1, 2, 3, 4, 5, c, L, represent the several
longitudinal movable notched combination bars and lock bar. 1, 2, 3, 4, 5ª
represent one bank of keys; 1, 2, 3, 4, 5b represent a second bank of keys,
and 1, 2, 3, 4, 5° a third bank of keys.
DD represent the rock shafts having arms f with which the stems of the keys
engage. d represents arms attached to said rock shafts, whereby the motion of the
rock shafts causes the longitudinal movement of the notched bars.
00 represent the key levers of any type writer with which the mechanisın is to
be used, and M represents push rods, which are pivoted to said levers 0 for
transmitting motion from a striking bar to said levers. Each of the push rods M
has on its front side a cam m². On the push rod shown in Figure 2 a projection m³
is formed which acts on a buffer bar Y to be hereinafter explained, but the ordinary
push rods do not have this projection and it and the buffer bar are to be disregarded
for the present.
The mechanisin above described is substantially like the corresponding mechanism
which is shown and described in detail in the other application referred to, and it has
the same mode of operation,-wherefore it is believed that it is unnecessary to give a
more extended description of said parts in this application.
A series of letter bars G which are pivoted on a transverse rod g³ extend over the
combination bars and normally rest upon one or more of the stubs between the notches
in said combination bars, being severally under the influence of the springs gl. To

page_text: this extent, this letter bar is substantially like the letters bars described in said other
application; but the letter bars instead of acting directly upon the push rods M, to
move them beneath the striking bar, as they do in the machine described in said
other application, merely act as triggers which normally hold and prevent the action
of independent mechanism for moving said push rods. This independent mechanism
consists of a triple lever E for each push rod and letter bar. All of these
triple levers are pivoted upon upon a transverse rod e, and are provided with
arms e, e², e, extending respectively downward, upward and forward. And each
triple lever is under the influence of a spring e acting upon the top of the arm e³, and
tending to rock said lever so that its arm e¹ is moved rearward. The downwardly
extending arm el of each triple lever is provided with a toe et which is adapted to
engage with the push rod M, when the lever E is released, with the result of moving
said push rod beneath the striking bar. On the rear end of the letter bars is a
tooth gwhich engages with the lower end of the arm e' and prevents its rear-
ward motion. The forwardly extended arm e³ is bent downward and has at its lower
end a bevelled finger, which engages with the bevelled upper end of an arın g²
projecting upwardly from the letter bar. The third arm e extends upwardly and
lies just behind but in contact with the trigger bar F. This trigger bar is secured
to the tops of two arms f, which are pivoted at their lower ends to the framework of
the machine.
The striking bar K, which extends transversely of the machine so that it may
act upon any push rod, is secured at its ends to side bars kl, which are pivoted
(preferably on a transverse rod k³) to the sides of the machine. At the middle of
the machine two curved arms kk are secured to the striking bar, and extend
therefrom upward and forward, and they are united at their upper ends and near the
striking bar by two cross bars 2 and 3. An arın, k, which is connected with the
cross bar, pivoted at its lower end in line with the pivots of the side bars, preferably
on the transverse rod k³. These two side bars k³, striking bar K curved arms k k,
cross bars k² k³, and arm k+, are all rigidly connected and constitute a striking bar
frame, which swings upon the axis of the rod k³.
The upper end of the arın klies between the two adjustably fixed rubber buffers ko k³,
which it strikes as the said frame is moved forward and backward; these buffers
acting as stops and taking up the jar at both ends of the movements of said frame.
The said frame is moved backward and downward, to cause the actuation of a key
lever O of the type writer by a spring T which is held between a fixed cross bar t
forming a part of the framework of the machine and the arm k of said striking bar
frame.
The frame is returned to its normal position by a power device which is released
for this purpose when the striking bar has completed its downward stroke. In the
construction shown, this power device consists of four wiper arms n which successively
engage with a step which is secured to the striking bar frame. These wiper arms
are set into the face of the escapement wheel N which is fast on a shaft S, which is
subject to a constant force, as a spring, tending to revolve it. The source of this
force is not shown in the drawing, because any suitable mechanism for the purpose
may be employed.
The power is liberated to operate the said shaft by an escapement which is actuated
by the striking bar frame. The escapement as shown consists of the four tooth
escapement wheel N fast upon the shaft S, which is held at rest by a pallet P having
a tooth p which engages with the teeth of said escapement. wheel. The tooth p is
preferably pivoted to the pallet, and has an arm pl whose movement is limited by the
screw head p2 and by a rubber buffer på interposed between said arm and the pallet.
An adjustable spring pt interposed between the front arm p5 of the pallet and the
fixed bracket f¹ holds the tooth against the escapement wheel. A rearward
prolongation p of said pallet lies in the path of an adjustable screw point / carried
by one of the curved arins h of the striking bar frame; and when the striking har
frame has completed its operative movement, this screw point strikes the pallet
arm p6, and by moving it, withdraws the tooth p from the escapement wheel. The

page_text: shaft. S thereupon revolves, one of the wiper arms n engages with the step k³, and
the striking bar frame is lifted. When it reaches its highest point, the pallet
tooth engages with the next tooth of the escapement wheel and prevents further
movement of the shaft. At the same time a spring pawl U engages beneath the
striking bar K and prevents its movement downward.
This pawl U is pivoted to a fixed bracket 2 and is pressed toward the striking bar
by a spring u. A bent lever is pivoted upon the same pivot to the same bracket.
This lever has two arms u¹ u², of which the former extends forward to a point where
it may come in contact with the cross bar ³ on the striking bar frame. The other
arm u² extends rearward, passing beneath an angle arm u³, secured to the spring
pawl U.
An adjustable screw passing through the said arm hears upon the said
lever arm u². A spring us acting upon the arm u¹ exerts a force tending to move
said arm forward, and consequently lift the arm u². And this lifting of the arm u²
withdraws the pawl U from its engagement with the striking bar K.
The lever arin u² is prevented from being lifted under ordinary conditions by a
pawl R, which passes through a slot in said lever arm u², and has a tooth r engaging
with said lever arm. This pawl is pivoted to the bracket t2, and an arm is rigidly
secured to this pawl. The upper end of this arm enters a slot in a flat spring W
which is attached to the trigger bar F. On the striking bar frame is a cam plate klo,
which is adapted to engage with the lever arm u¹ and to move it in opposition to its
spring us.
The operation of the described mechanism is as follows: One or more of the
combination bars is moved and the notches are aligned beneath a letter bar G which
is moved into the slot thus formed by its spring g¹. This movement releases the
corresponding triple lever E which is moved by its spring e. The toe et thereupon
moves the corresponding push rod M beneath the striking bar K. The upper arm e²
moves the trigger bar F forward. The spring W thereupon draws upon the arm
thereby moving the pawl R forward. This releases the arm u² of lever, and
thereupon the spring u rocks the lever arm u¹ against the cross bar k³. The said
movement of said lever moves the pawl U and releases the striking bar. It descends
under the influence of the spring and forces down the push rod. The cam on the
push rod noves the triple lever E in the reverse direction, and the bevelled finger e³
engages with the bevelled surface on the arm g² on the letter bar, thereby lifting the
letter bar and permitting the lock bar L to move beneath it, whereby the combination
bars resume their normal position.
The cam plate 10 engages with the lever arm ul and moves it in opposition to its
spring us. The other arm u² is engaged automatically by the pawl r, which has
been permitted to resume its normal position, because the trigger bar was returned
to its normal position by its spring, when the triple lever was moved by the cam on
the push rod. This leaves the pawl U free to engage with the striking bar when the
latter has been raised. The spring W was lifted and upheld out of contact with the
pawl r, by a finger u' on the end of the lever arm u², when the spring us lifted it,-
wherefore the pawl R was relieved of all pressure which would interfere with its
movement by its spring r³.
Just as the striking bar reaches its lowest position, the screw k carried by the
striking bar frame engages with the pallet arm p6, thereby releasing the escapement.
wheel, whereupon the shaft S immediately revolves, and one of the wiper arms
engages with the step and lifts the striking bar frame. When it has reached its
highest point, the pawl U automatically engages with the striking bar and holds it
up, as before explained. The pallet tooth is moved by spring p and engages with the
escapement wheel N. All of the parts have now been returned to their normal
position, ready for a repetition of the described action. .
When the mechanism described is used in connection with a typewriter having a
shift key for capital letters or other purposes, a new condition is presented in that
more force is required to move the shift key and type key than is required when the
type key alone is struck, and therefore if the striking bar descended always with the
same force, the stroke would either be too strong in ordinary cases, or too weak when

page_text: the shift key was struck. To provide for this condition the force of the spring which
actuates the striking bar is increased to the amount required when the shift key is
used, and a inovable buffer is supplied which ordinarily counteracts the excessive
force of the spring, but is moved out of the way when the shift key is struck.
Figure 2 of the drawings shows this construction. Y is a buffer bar preferably
located on the medial line of the machine and having its upper end y forked and
extending under the striking har K. The lower end of the buffer bar is pivoted to a
rocker arm y carried by a rock shaft y3 which is journalled in a suitable standard y*.
A spiral spring y surrounds the rock shaft and is connected with the arm y2 or some
suitable crank arın carried by the rock shaft. This spring in tending to unwind
presses the buffer bar upwards, the upward movement being limited by an arm y
extending from the rock shaft impinging against a set screw y carried by the
standard and forming a stop for such arm. A spring y' suitably supported and bearing
against the buffer bar, tends to keep the upper end thereof under the striking bar. The
result of this mechanism is that in ordinary cases when the striking bar descends
under the force of the spring T the buffer bar is forced downward, winding up the
spring y', which spring counteracts the excessive force of the spring T and aids in
returning the striking bar to its normal position at the completion of the stroke.
When, however, the shift key is to be struck, the push rod M which acts in this case
as a lug m³ on its back side, which contacts with the buffer bar and pushes it from
under the striking bar against the action of the spring y¹ so that in this case the
striking bar descends with the force of the spring T uncounteracted. When the
striking bar is elevated the spring y' moves the buffer bar beneath it. It will be under-
stood that the form of buffer, or as I term it "stroke equalizer," shown is simply illus
trative and may be greatly modified. If desired it may be located at the top of the
machine or in other places.
Having now particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondents, and in what manner the
same is to be performed, I declare that what I claim is :-
1. The combination of the notched combination bars, a plurality of independently
movable spring pressed letter bars, each having a retaining jaw, push rods for
operating the type writer levers and a striking bar, with the corresponding spring
pressed levers E which are severally adapted to engage with and move the correspond-
ing push rods in range of the striking bar, and are themselves engaged and held in
opposition to their springs by the jaws on the corresponding letter bars, substantially
as and for the purpose specified.
2. The combination of the notched combination bars, a plurality of independently
movable letter bars each having a retaining jaw, a bevelled arm, and push rods having
cams and a striking bar, with the independent spring pressed levers E which are
engaged by the jaws on the corresponding letter bars and held in opposition to their
springs, each of said levers having a toe for engagement with the corresponding push
rod and its cam, and a bevelled arm for engagement with the bevelled arm on the
corresponding letter bar, substantially as and for the purpose specified.
3. The combination of the notched combination bars, a plurality. of independently
movable spring actuated letter bars each having a retaining jaw and a bevelled arm,
the push rods having cams, the striking bar, retaining mechanism preventing the
movement of the latter, and a trigger bar for operating said retaining mechanism,
with the spring pressed three arm levers E, of which one arm of each lever is engaged
by the jaw on the corresponding letter bar and provided with a toe for engagement
with the corresponding push rod and its cam, another arm has a bevelled surface
which is for engagement with the bevelled arın on the letter bar, and that arm is
adapted to operate the trigger bar, substantially as and for the purpose specified.
4. The combination of the striking bar and its frame, a spring for moving it down
in the operative direction, a retaining pawl for preventing such movement, a driven
operating shaft, wiper arms secured thereto and adapted to engage with and lift the
striking bar, an escapement wheel on said shaft, a pallet having an arm which extends

page_text: into the path of some part of the striking bar frame, whereby said pallet is withdrawn
from the escapement wheel, and means for withdrawing the retaining pawl, substan-
tially as and for the purpose specified.
5. The combination of the push rods and mechanism for moving them into the
path of the striking bar, with a pivoted striking bar frame, the striking bar, a spring
for moving said bar in the operative direction, a spring pawl for preventing
such movement, mechanism for withdrawing said pawl, and mechanism for return-
ing said striking bar frame to its normal position, substantially as and for the purpose
specified.
6. The combination of the pivoted striking bar frame, a spring for moving it in
the operative direction, a spring pawl for preventing such movement, the trigger
bar, mechanism for moving it, mechanism intermediate of said trigger bar and pawl
for withdrawing the latter, a driven operating shaft, wiper arms carried thereby for
lifting the said frame in opposition to its spring, an escapement wheel, a spring
actuated pallet which extends into the path of some part of said frame whereby the
pallet is withdrawn, substantially as and for the purpose specified.
7. The combination of the striking bar frame, and mechanism for moving it in
the operative direction, with a spring pawl U having an angle arm u³, the lever
having an arm u² which passes beneath the angle arm u³, a spring for actuating said
lever, a retaining pawl R for engagement with said lever, to hold it in opposition to
its spring, the trigger bar, and mechanism intermediate of said trigger bar and
pawl R whereby the latter is withdrawn, substantially as and for the purpose
specified.
8. The combination of the striking bar frame, mechanism for operating it, and a
cam plate ko carried by said striking bar frame, with the spring pawl U which
engages with and prevents the downward movement of said frame, said pawl having
an angle arm u³, a lever having one arm u² which is in position to engage with said
arm and withdraw the pawl, and another arm u¹ which is adapted to be engaged
by said cam plate, a spring pressing said arm toward said cam plate, a spring retain-
ing pawl R adapted to engage with the arm u¹ to prevent the movement of the lever
by its spring, the trigger bar, and intermediate mechanism whereby the movement
of the trigger bar withdraws said retaining pawl, substantially as and for the purpose
specified.
9. In a key board mechanism for typewriters or analogous machines, where it is
desired to deliver blows of varying force, the combination of means adapted to deliver
the maximum blow, mechanism adapted to counteract a portion of such blow, and
means for throwing out of action said counteracting mechanism, substantially as and
for the purpose specified.
10. The combination of a striking bar, a spring adapted to operate the same with
a maximum force, a counteracting spring normally reducing the force of the stroke,
and mechanism for throwing out of action said counteracting spring, substantially as
and for the purpose specified.
11. The combination of a striking bar frame, the spring T of greater force than
normally required tending to operate the same, a buffer bar Y normally in the path
of the striking bar frame and adapted to be moved by the latter, a spring y' tending
to counteract such movement of the buffer bar, and means operated by certain push
bars for moving said buffer bar out of the path of the striking bar frame, whereby
the latter may be operated by the full force of the spring T, substantially as and for
the purpose specified.
12. The key board mechanism for typewriters and analogous machines, substantially
as herein shown and described.
DELL
T
1000
BOULT & WADE,
Agents for the Applicant.