Improvements in Typewriting Machines.
Year: 1897

page_text: Date of Application, 19th June, 1897-Accepted, 24th July, 1897
Improvements in Typewriting Machines.
I, JUSTIN GILBERT, a Citizen of the United States of America, and a resident
of 19 Board of Trade Building, Victoria, Province of British Columbia, Canada,
Official Stenographer, 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:
My invention relates more particularly to an attachment for typewriting
machines for moving the carriage backward step by step one letter space at a time
with absolute precision at any desired speed so that such back-spacing may be
perfectly accomplished as rapidly as 'the ordinary or front spacing or as the letters
of the machine may be struck by the expert operator, or it may be perfectly
accomplished slowly by a slow operator; and it consists essentially of a dog
pivoted to a movable dog-carrying plate and connected with a key-lever so that
when the key is depressed the dog is moved into engagement with a rack-bar
attached to the paper carriage of the machine, or with the escapement rack-bar
itself, as the case may be, and draws the paper carriage backward the required
distance to allow the escapement dogs of the machine to spring into engagement
with the next proceding tooth of the escapement rack-bar, at which point the
carriage is at once abruptly and forcibly stopped by means of the apparatus thus
limiting the movement of the carriage backward with invariable accuracy, and at
the same time by overcoming the inertia of the backward movement of the carriage
instantaneously making it rebound back in the normal direction again until
stopped by the escapement dogs which have assumed their normal position again
so that by means of such carriage-locking device the whole operation may
be done in
very small fraction of a second, and repeated many
times in a second, and all liability of moving the carriage backward more
than one space at a time is overcome. My invention is applicable to
type-writing machines having their carriage under constant stress tending to
move it from right to left as in the Densmore, Remington, Smith Premier, Cali-
graph, Yost and other similar class of machines. My invention also consists in
certain details of construction that will be hereinafter fully described and
specifically pointed out in the claims.
In order that my invention may be clearly understood, and readily carried into
effect, I will proceed aided by the accompanying drawings, fully to describe the
same.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a view showing one form of my invention.
Figure
2 is an enlarged inside view of the dog and movable dog-carrying plate
of this form, the operative position of the parts being shown in dotted lines.
Figure 3 is a detail top view of a typewriting machine having applied thereto
another form of my device.
Figures 4 and 5 are detail views of this form showing the device in and out
of engagement with the rack-bar.

page_text: Figures 6, 7 and 8 show still another form of my invention.
In the said drawings, and referring more particularly to Figures 1 and 2, A is a
movable dog carrying plate in the form of a rectangular frame, and it has pivoted
thereto at C the heel of a dog B which is shown in the form of a bell-crank. lever.
One end of this lever is connected by a rod G to an arm of a bell-crank lever F
pivoted by its heel at H to a bracket P, and the other arm of the bell-crank lever F
is connected to a key-lever J by means of a rod I. F¹ represents a spring for
returning the lever F to normal position after being depressed by the key-lever J,
and this spring also necessarily returns all the other parts of the device with the
exception of the plate A, to their normal position where they are all stopped by
the key-lever having gone as far upward as it will go. The plate A is returned
to normal position against the stop D by the spring a; the springs F1 and a also
aid each other more or less.
The operation of this form of the device is as follows: The parts are normally
in the position shown in Figures 1 and 2, with the tooth b of the dog B resting
in close proximity to the rack-bar K; but not close enough to touch the rack-bar
while the rack-bar is moving in actual writing, and it is held in this position
by the rod G which will not permit it to go against the rack-bar until the rod G is
operated upon, the plate A being held in position against the stop D by the spring a.
The key-lever is then depressed, moving the rod G to the right of the machine
and turning the dog B on its pivot Cuntil its tooth b strikes between the teeth
of the rack-bar and can go no further in that direction, then the plate A turns on
its pivot A¹ and the rack-bar is pulled backward until the escapement dogs of the
typewriting machine have engaged the next tooth in rear to the one they held
before; the distance which the rack-bar must be pulled is necessarily greater than
the space of one rack-bar tooth in order to admit of the escapement dogs
thus engaging the next tooth, the distance differing with the different
forms of the escapement dogs on the different makes of typewriting
machines, and ranging generally from about two to about four or
five rack bar tooth spaces; as soon as the rack-bar has been carried far enough
for the escapement dogs to have engaged the next rack-bar tooth as aforesaid,
the plate A strikes against the stop E, which arrests any further movement of
the device in that direction, however, the momentum given to the machine carriage
in the movement just explained would cause it to go on beyond the desired point
unless its motion were also arrested by a positive stop; such positive carriage stop
is effected by means of the dog itself being held by its pendent lug 61 climbing
onto and resting on the stop L and preventing withdrawal of the tooth b from the
rack-bar, the rack-bar not admitting of any movement away from the dog, the
slanting side of the rack-bar notch thus strikes against the tooth of the dog which
effectually locks the carriage, and starts it back in the opposite direction again;
the two springs above referred to return the apparatus to its normal position, the
carriage returning forward at the same time until it rests in its normal position
against the escapement dogs which have engaged the next rack-bar tooth, in the
rear, as aforesaid, and the carriage then stands one notch backward from where
it stood before the operation. By means of this carriage stop, the quicker the
movement of the back-spacing apparatus the quicker is the carriage thrown back
into position as aforesaid, so that the speed with which it may be operated is
practically unlimited and at the same time it may be operated slowly, and any
uncertainty as to the distance spaced is rendered impossible.
Referring to Figures 3 to 5 inclusive in which I have shown the device applied
to a typewriting machine having the racket-bar K¹ in a horizontal position on the
carriage; B¹ represents the dog, which is, as in the other case, in the form of a
bell-crank lever, and A2 the movable plate which is pivoted at A³. The plate
is here shown as a short and flat strip against which the spring a¹ bears for holding
it in the position shown in Figure 5. E' and L' represent the two stops corresponding
with the stops D and E respectively above mentioned, and L' accomplishes also
in addition the work accomplished by the stop above referred to. The operation

page_text: of this form is the same as in the one above described. The tooth 6 of the dog
fills up the space
between the stop L' and the rack-bar at the end of the movement
as in the former case, so that the rack-bar cannot pass any farther, the dog
locking instantaneously with the lug bearing on the stop L' and preventing
it from going too far and starting it back again in the opposite direction, as before
explained.
SO
that
movement
any
of
with
Referring to Figures 6, 7 and 8, which is my preferred form B³ represents a
bell-crank or approximately L-shaped dog which is pivoted on the movable
plate A by its heel at C² the movable plate being pivoted at Ato-the-frame of the
machine. The movable plate is approximately C-shaped and the respective
eds S and T serve as the stops, performing exactly the same office as the three
stops mentioned in the first instance, and the two in the second instance. These
ends S and T are turned up and flanged so as to strike against the dog. The
toothed end of the dog is also bent up so that it engages the rack-bar teeth when
in use, while at the opposite end thereof, the rod G and the movable support
at the end T, are free to pass on one side of the rack-bar without touch-
ing the same. The spring keeps the end T normally in position against
the dog,
the dog when disengaged
the rack-bar turns the plate A' upon its pivot A; the rod G therefore
holds the dog in position close to and ready to engage the rack-bar when
operated as in the former cases. When the rod G is operated upon as before
explained, the plate A turns on its pivot A and the tooth of the dog comes in
contact with the rack-bar in one of the notches, then the dog turns on its pivot C2,
the plate A continuing to turn on its pivot, and the rack-bar is drawn backward
the required distance as aforesaid, when the end S strikes against the dog and
instantly arrests all further movement in that direction of both the apparatus and
the carriage itself, as shown in Figure 7 for the rack-bar not admitting of any
but lateral motion cannot pass over the dog; and the returning movement of
the carriage and the apparatus then takes place as in the other cases, giving the
desired speed and accuracy in back-spacing.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. A back-spacing attachment comprising a pivoted dog-carrying plate, a dog
having a tooth adapted to engage the rack-bar of a paper carriage and pivoted to
the said dog-carrying plate, a stop limiting the rearward movement of the dog-
carrying plate and means whereby the dog is actuated to first insert its tooth into
a rack-bar space and then to move the carriage and to positively lock the dog,
dog-carrying plate and carriage together from further movement until released;
substantially as described.
2. A back-spacing attachment comprising a pivoted dog-carrying plate, a dog
having a tooth adapted to engage the rack-bar of a paper carriage, and pivoted to
the said dog-carrying plate, a stop limiting the rearward movement of the
dog-carrying plate, a key-lever, and connections between the said dog
and the said key-lever whereby the dog is actuated to first insert its tooth into a
rack-bar space and then to move the carriage and to positively lock the dog,
dog-carrying plate and carriage together from further movement until released;
substantially as described.
3. A back-spacing attachment comprising a pivoted dog-carrying plate, a dog
having a tooth adapted to engage the rack-bar of a paper carriage, and pivoted to
the said dog-carrying plate, a stop limiting the rearward movement of the dog-
carrying plate, means whereby the dog is actuated to first insert its tooth into
a rack-bar space and then to move the carriage and to positively lock the dog
dog-carrying plate and carriage together from further movement until released,

page_text: a spring returning the dog-carrying plate and a stop limiting the forward
movement of the dog-carrying plate; substantially as described.
4. A back-spacing attachment comprising a pivoted dog-carrying plate, a dog
having a tooth adapted to engage the rack-bar of a paper carriage and pivoted to
the said dog-carrying plate, a stop limiting the rearward movement of the dog-
carrying plate, a key-lever, connections between the said dog and the said
key-lever, whereby the dog is actuated to first insert its tooth into a rack-bar
space and then to move the carriage and to positively lock the dog, dog-carrying
plate and carriage together from further movement until released, a spring
returning the dog-carrying plate, and a stop limiting the forward movement of
the dog-carrying plate substantially as described.
5. The back-spacing attachment comprising an approximately C-shaped and
pivoted dog-carrying plate, having stops an approximately L-shaped dog having a
tooth and pivoted to the dog-carrying plate and working between the stops, means
for swinging the dog and dog-carrying plate, and a spring for returning the
Cog-carrying plate; substantially as described.
6. A back-spacing attachment comprising a pivoted dog-carrying plate, a dog
having a tooth adapted to engage the rack-bar of a paper carriage and pivoted
to the said dog-carrying plate, a stop limiting the rearward movement of the dog-
carrying plate, a spring returning the dog-carrying plate, a stop limiting the
forward movement of the dog-carrying plate, a bell-crank lever, a horizontal rod
connecting the bell-crank lever to the dog, a key-lever and a vertical rod connecting
the key-lever to the hell-crank lever; substantially as described.
Dated this 19th day of June 1897
WHITE & WOODINGTON,.
27, Southampton Buildings, London, Agents.
WHITE & WOODINGTON,
27, Southampton Buildings, London, Agents.