Improvements in or relating to Escapement Mechanism for Typewriters.
Year: 1892

page_text: Date of Application, 11th Oct., 1892
Complete Specification Left. 11th Aug., 1893-Accepted, 23rd Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in or relating to Escapement Mechanism for
Typewriters.
We, EDWARD SMITH HIGGINS and HENRY CHARLES JENKINS Engineers, of
51 and 53 Handforth Road, Clapham, in the County of Surrey, do hereby declare
the nature of this invention to be as follows:-
This invention relates to the escapement mechanism of typewriters by which the
Hitherto this has
paper carriage or platen is fed along after each letter is struck.
usually been effected by a watch spring contained in a barrel around which a chain
is coiled and connected with the carriage so that when the carriage is pulled to one
extreme of its travel the chain is unwound the spring winding up the chain and
drawing on the carriage as the action of the machine allows it. The movement of
the carriage is controlled by one or more racks and toothed dogs engaging there-
with a straight rack of about the length of the carriage being employed for this
purpose. By our present invention we are enabled to combine the spring barrel
and escapement mechanism as will presently appear.
The details may be varied, but the following description will suffice for the
understanding of the invention. The spring barrel is provided with a removable
ring having teeth upon its periphery and connected with the barrel either by an
inner series of teeth or suitable stops or the like the arrangement being such
that while the barrel is in its normal position the ring can only turn with the
barrel, but when the barrel is moved in the direction of its axis it cau be slipped
clear of the ring and when in that position can be revolved quite independently of
the ring. A suitable slide carries a dog or toothed rack which being fixed in the
slide will be called the fixed dog which is adapted to engage with the teeth of the
ring when the slide is moved in that direction. This it does when the slide is
moved forward by the action of depressing a key or spacing lever the fixed dog
then engaging with the teeth and preventing the barrel from turning. The slide
also carries a short toothed rack adapted to engage the teeth of the ring the ruck
being pressed in the direction opposite to that in which the ring will move under
the influence of the main spring by a weaker spring. The rack is normally in
engagement with the ring and by the operation of the main spring is pulled over
to the end of its stroke against a suitable stop provided on the slide or framework.
When the key is depressed, the slide would move so that the fixed dog engages
with the teeth and the rack is disengaged from the teeth and consequently the
weak spring pushes the rack along until it meets with a stop the exact position of
which may vary according to the length of the letter to be printed. When the
key is released the slide under the influence of its spring returns to its normal
position removing the fixed dog from engagement with the teeth of the barrel rim
and re-engaging the teeth of the rack which being overcome by the strength of
the main spring gives way until it reaches its stop thus allowing the barrel to turn
the required distance, drawing the carriage with it. The slide may be reciprocated
by any convenient means and is preferably connected with the key or spacing lever
by a bell-crank lever, a link or other suitable means.. The means for deciding
the length of travel of the rack may vary according to the construction of the
machine to which this mechanism is applied, but we prefer to effect it by the
introduction of spacing bars between. the end of the slide or a shoulder or stop
provided for the purpose and some fixed point in the machine as set forth in our
former Specification No. 9425 of 1888. In a machine in which the same amount
of space
is awarded to cach letter the rack would always travel the same distance.
The arbor of the spring barrel may be squared for the purpose of winding it up

page_text: and may also have a spring pressing upon it so as to keep it in its normal position
which would be against a bar which may be pivotted to the paper carriage so that
when the bar is depressed the arbor is forced down taking the spring barrel with it
until it is free from the previously described toothed rim; the movement of the
arbor will be controlled by the spacing lever or by a special key.
If preferred the arbor may be a fixture and the barrel may be caused to move
end wise upon it by means of a clutch working in, a groove upon the barrel, or the
toothed ring may be thus moved. Also, the separate toothed 'ring may be dispensed
with and the teeth formed directly on the barrel in the usual manner of a spring
barrel, the barrel in this case being moved so as to clear it from the escapement
teeth. Other means may however be adopted for disengaging the escapement
teeth and those of the spring barrel for the purpose of releasing the paper
carriage. For example the slide carrying the escapement teeth could be moved
bodily.
If desired instead of connecting the spring barrel with the paper carriage, by a
cord or chain in the usual manner a portion of the barrel may be toothed engaging
with a rack fixed upon or connected with the paper carriage so that as the barrel
revolves the carriage will travel.
Dated this 11th day of October 1892.
W. P. THOMPSON & BOULT,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in or relating to Escapement Mechanism for
· Typewriters.
We, EDWARD SMITH HIGGINS and HENRY CHARLES JENKINS, Engineers, of
51 and 53 Handforth Road, Clapham, in the County of Surrey, 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: -
This invention relates to the escapement mechanism of typewriters by which the
paper carriage or platen is fed along after each letter is struck. Hitherto this has
usually been effected by a watch spring contained in a barrel around which a chain
is coiled and connected with the carriage so that when the carriage is pulled to one
extreme of its travel the chain is unwound the spring winding up the chain and
drawing on the carriage as the action of the machine allows it. The movement of
the carriage is controlled by one or more racks and toothed dogs engaging there-
with a straight rack of about the length of the carriage being employed for this
purpose. By our present invention we are enabled to combine the spring barrel
and escapement mechanism as will presently appear.
The details may be varied, but the following description will suffice for the
understanding of the invention. The spring barrel is provided with a removable
ring having teeth upon its periphery and connected with the barrel either by an
inner series of teeth or suitable stops or the like the arrangement being such
that while the barrel is in its normal position the ring can only turn with the barrel,
but when the barrel is moved in the direction of its axis it can be slipped clear of
the ring and when in that position can be revolved quite independently of the ring.
A suitable slide carries a dog or toothed rack which being fixed in the slide will be
called the fixed dog which is adapted to engage with the teeth of the ring when the
slide is moved in that direction. This it does when the slide is moved forward by
the action of depressing a key or spacing lever the fixed dog then engaging with
the teeth and preventing the barrel from turning. The slide also carries a short
toothed rack adapted to engage the teeth of the ring the rack being pressed in
the direction opposite to that in which the ring will move under the influence of the
main spring by a weaker spring. The rack is normally in engagement with the
ring and by the operation of the main spring is pulled over to the end of its stroke

page_text: against a suitable stop provided on the slide or framework. When the key is
depressed the slide would move so that the fixed dog engages with the teeth and
the rack is disengaged from the teeth and cousequently the weak spring pushes the
rack along until it meets with a stop the exact position of which may vary
according to the length of the letter to be printed. When the key is released the
alide under the influence of its spring returns to its normal position removing the
fixed dog from engagement with the teeth of the barrel rim and re-engaging
the teeth of the rack which being overcome by the strength of the main spring
gives way until it reaches its stop thus allowing the barrel to turn the required
distance, drawing the carriage with it. The slide may be reciprocated by any
convenient means and is preferably connected with the key or spacing lever by a
bell-crank lever, a link or other suitable means. The means for deciding the
length of travel of the rack may vary according to the construction of the machine
to which this mechanism is applied, but we prefer to effect it by the introduction of
spacing bars between the end of the slide or a shoulder or stop provided for the
purpose and some fixed point in the machine, as set forth in our former Specification
No. 9425. In a machine in which the same amount of space is awarded to each
letter the rack would always travel the same distance.
The arbor of the spring barrel may be squared for the purpose of winding it up
and may also have a spring pressing upon it so as to keep in its normal position
which would be against a bar which may be pivotted to the paper carriage so that
when the bar is depressed the arbor is forced down taking the spring barrel with it
until it is free from the previously described toothed ring; the movement of the
arbor will be controlled by the spacing levor or by a special key.
If preferred the arbor may be a fixture and the barrel' may be caused to move
end wise upon it by means of a clutch working in a groove upon the barrel, or the
toothed ring itself may be thus moved. Also, the separate toothed ring may be
dispensed with and the teeth formed directly on the barrel in the usual manner of
a spring barrel, the barrel in this case being moved so as to clear it from the
escapement teeth. Other means may however be adopted for disengaging the
escapement teeth and those of the spring barrel for the purpose of releasing
the paper carriage. For example the slide carrying the escapement teeth could be
moved bodily.
If desired instead of connecting the spring barrel with the paper carriage by a
cord or chain in the usual manner a portion of the barrel may be toothed engaging
with a rack fixed upon or connected with the paper carriage so that as the barrel
revolves the carriage will travel.
In the accompanying drawings
Figure 1 is a vertical section through an escapement mechanism constructed in
accordance with this invention.
Figure 2 is a plan of the same partly in section.
Figure 3 is a vertical section taken upon a plane at right angles to that of
Figure and showing the mechanism in its ordinary operative position.
Figure 4 is a view similar to Figure 3 but showing the spring barrel disengaged
from the escapement mechanism.
Figure 5 is an inverted plan and
Figure 6 is a detail.
Figures 7 and 8 are sections through the spring barrel of a modification.
Like letters represent like parts throughout the drawings.
A is the paper carriage and B a portion of the fixed frame-work of the machine.
C is the spring barrel around which is coiled a wire chain or equivalent D connected
at both ends with the paper carriage A and having one or more coils round the
spring barrel C so as to take sufficient hold upon it and ensure that when the spring
barrel turns it will also move the carriage as will be well understood. The spring
barrel C has upon it a toothed rim C¹ being part of the barrel or rigidly secured
to it and the coiled spring inside the barrel ia secured at its outer end thereto and
at its inner end to the arbor E which underneath the barrel carries a collar E

page_text: denticulated on its under face as shown, the teeth being engaged by the detent E
pivotted at E in the yoke F which is itself pivotted at F' to the rigid frame-work B
the object of the toothed collar E' and detent E being to enable the spring to be
wound up to the required tension and then held by the detent whose longer or
heavier end extends through an opening in the yoke Fas clearly shown in Figure 3
so that the detent naturally remains in engagement with the toothed collar E¹.
The collar is fast upon the arbor E so that the spring may be wound up by means
of the collar E' which may be provided with holes for a pin spanner or may be
squared or otherwise suited to the purpose.
Outside the toothed rim C' of the barrel C is a ring G provided upon its inner
periphery with teeth corresponding with those upon the barrel so that the ring may
be carried round with the barrel and upon its outer periphery with ratchet teeth G₁
forming a portion of the escapement mechanism. This ring is not absolutely fixed
but is carried in a recess formed in the under side of the framing B as shown in
Figure 3 and is prevented from falling out downwards by a sliding plate H which
is practically a thin flat annulus with an opening in the centre not quite so large as
the diameter of the escapement ring G and having two projecting portions,
one H Figures 1 and 2, which carries the fixed dog 1 (that is fixed upon the
sliding plate H. but moving with it) and has a slot H' Figures 2 and 5 through
which a small hended screw H passes holding the plate H up against the under
side of the framing B and preventing it from travelling more than its appointed
distance. Diametrically opposite the projection H' is another projection H
through which is a similar slot H and screw H' for the same purpose as before.
The portion H carries the toothed rack J adapted to travel longitudinally in any
suitable guides H' upon the plate H, the travel of J in one direction being limited
by a stop J in the framing B-or this stop may be fixed upon H and engage with
a slot in the rack or other equivalent means may be employed for terminating the
travel of J in this direction. The travel of J in the opposite direction is effected
by a spring K whose tendency is in the direction of the arrows in Figures 2 and 5.
The travel of J in this direction is terminated by a suitable stop or preferably by
means of spacing bars L engaging with the end of J or with steps J2 upon J in
the manner set forth in our previous Specification No. 942589.
The normal position of the sliding plate H is that set forth in Figures 1 and 2
which places the teeth of the rack J in engagement with the teeth G¹ of the ring G
but when a key or spacing levor is operated the plate H is drawn forward in the
direction of the arrow in Figure 2 so that the rack J is disengaged from the teeth
of the ring G and the fixed dog I is brought into engagement therewith. Normally
the strength of the spring in the barrel C forces the rack J into its extreme
position as in Figures 2 and 3 overcoming the pressure of the spring K but after
the previously described movement when the rack J is disengaged from G the
spring K asserting its power forces the rack J back to the extremity of its travel
in the direction of the arrow in Figures 2 and 3, the extent of that movement being
determined as above explained. Supposing that movement to be equal to two teeth
of the ring G when the key or spacing lever is released the plate H returns under
the influence of the spring I Figures 1 and 2, to its position in Figures 2 and 5
placing the rack J again into engagement with the ring G and disengaging the
fixed dog I. The spring in the barrel C now again asserts itself, overcoming the
weaker spring K and drawing the rack J forward as far as its stop will permit
when the spring barrel is stopped from turning further aud in the suggested case
having moved to the extent of two teeth and by reason of the wire or chain D
drawn the paper carriage along with it to that extent. The tension of the spring H
can be regulated by the screw H' Figures 1 and 2 as will be well understood. The
plate H may be connected with the key or spacing mechanism in any desired
manner; in Figure 1 a bell crank lever M operated by key and spacing mechanism
is shown for this purpose.
To enable the paper carriage to be moved independently of the escapement
mechanisin the following means may be adopted,

page_text: A yoke N pivotted at N' to the framing B bears by the screw N* upon the upper
eud of the arbor E and upon this yoke bears also the bar N Figures 3 and 4 which
may be either the key provided for that purpose or connected therewith. In
normal working the parts are as shown in Figure 3 but when it is desired to move
the carriage and for this purpose to disengage the spring barrel C from the
escapement mechanism the bar N is depressed pushing down the yoke N into the
position shown in Figure 4 and carrying with it the arbor E spring barrel C and
yoke F and compressing the spring F. The toothed rim C¹ of the latter is thus
moved clear of the escapement ring G when as the barrel C can be freely turned in
either direction the paper carriage can be moved as required and will be fixed
again when the bar N³ is released and the spring barrel consequently allowed to
return to its normal position in engagement with the escapement ring G under the
influence of the spring F which returns the yoke F to the position shown in
Figure 3.
In Figures 7 and 8 are illustrated a modification of the arrangement above
described in which the spring barrel C and arbor E do not move in order to
disengage the escapement mechanism, but a circular cover or casing O fitting upon
the spring barrel carries the toothed rim C¹ which engages with the escapement
ring G, the construction and operation of the escapement mechanism being as
already described. In this case the arbor E may be squared at the top and carry
a ratchet wheel E with which engages a spring pawl E pivotted upon the arm E
which supports the upper end of the arbor E whose lower end is carried in any
suitable fixed support. The casing is so formed as to provide a depressed
circular groove having teeth O' around it with which teeth engages a rack P
pivotted at P upon the paper carriage and all substantially the same length. With
this arrangement the wire or chain D is dispensed with and as the spring barrel C
rotates the teeth O' of the casing O which is so connected (as by the screw O'
passing through a slot in the casing and screwing into the spring barrel C)
engaging with the teeth of the rack P cause the latter and with it the paper
carriage to travel, the result being the same as in the case where the wire D was
employed. To disengage the toothed rim C' from the escapement ring G so as to
free the paper carriage from the control of the escapement mechanism the rack P
is turned upon its pivot P' thus raising the casing upon the barrel C into the
position shown in Figure 8 and lifting up with it the toothed rim C¹ until it is out
of engagement with the escapement ring G. The rack P may be operated in any
convenient manner by a key or button which being released the rack will return to
the position of Figure 7 under the influence of an appropriate spring which may be
applied to the rack itself or to the casing O.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is ;-
1. In a typewriter a spring barrel which also acts as part of the escapement
mechanism.
2. An escapement mechanism comprising a spring barrel with escapement teeth
and a sliding plate carrying one fixed and one movable dog or dog rack substantially
as described.
3. In a typewriter the combination with a spring barrel such as C of an
escapement ring such as G so arranged as to be readily connected with or
disconnected from the spring barrel substantially as described and illustrated in the
accompanying drawings.
4. In a typewriter the combination with a spring barrel such as C of an
escapement ring such as G substantially as described.
5. Engaging and disengaging the spring barrel of a typewriter with and from the
escapement ring by reciprocating it in the direction of its axis.
6. In a typewriter the combination with a spring barrel such as C having a
toothed rim C¹ of an escapement ring such as G bearing on its outer periphery

page_text: the escapement teeth and on its inner periphery teeth corresponding with those
of the rim C substantially as described and illustrated in the accompanying
drawings.
7. In a typewriter the combination with a spring barrel such as C adapted to be
reciprocated in the direction of its axis of an escapement ring such as G not
partaking of such movement with and from which in its reciprocations the spring
barrel alternately engages and disengages substantially as described and illustrated
in the accompanying drawings.
8. In a typewriter the combination with the spring barrel arbor E of a
denticulated collar such as El detent E2 and spring controlled pivotted yoke F
substantially as described and illustrated in the accompanying, drawings.
9. In a typewriter the combination with a spring barrel carrying escapement
teeth of a sliding plate such as H carrying a fixed dog such as I and a movable
dog or dog rack substantially as described and illustrated in the accompanying
drawings.
10. In a typewriter the combination with a sliding plate such as H carrying a
fixed dog such as 1 of a movable dog or dog rack such as J and a spring K the whole
constructed and operating substantially as described and illustrated in, the
accompanying drawings.
11. In a typewriter the combination with a spring barrel and paper carriage of a
rack carried by the paper carriage and engaging teeth turning with the spring
barrel substantially as described and illustrated in Figures 7 and 8 of the
accompanying drawings.
12. In a typewriter the combination with a spring barrel of a sliding casing such
as carrying at one end a toothed rim such as C and at its other end a recessed
toothed ring such as substantially as described and illustrated in Figures 7 and 8
of the accompanying drawings.
13. In a typewriter the combination with a spring barrel of a sliding casing or
cover such as O adapted to make aud break connection with an escapement ring
such G substantially as described and illustrated in the accompanying drawings:
14. In a typewriter the combination with the paper carriage of a pivotted rack
such as P P substantially as described and illustrated in the accompanying
drawings.
Dated this 10th day of August 1893
E. S. HIGGINS.
HENRY C. JENKINS..
W. P. Thompson & Boult,
Agents for the Applicants.