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Патент USA US2108112

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- Feb. '15,"19383
4F. EIBE‘RT
ESCAPEMENT
Filed Nov. 20, 1934-
`
-
2,108,112
2 Sheets-Sheet l
¿3102162559
Feb. 15,-1938.- l
F_. EIBERT
2,108,112
ESCAPEMENT
Filäed Nov. 2o, 1934
l2 sheets-_sheet 2
WM? ¿260%
2,108,112
Patented Feb. 15, 1938
rer
UNITED STATES
Fries
2,108,112
ESCAPEMENT
Fritz Eibert, Munich, G ermany, assigner to Rob
ert Wolff, Basel, Switzerland
Application November 20, 1934, Serial No. 753,796
In Germany April 3, 1934.
5 Claims.
(Cl. 197-88)
The present invention relates to an improved
escapement and more particularly to a paper
teeth having a safety catch which can be easily
manufactured and which can be used for con
carriage escapement for typewriters.
,_
In order to speed up the step by step displace
J ment o1" the paper carriage in typewriters and at
the same time to utilize the force exercised by
the carriage spring on the escapement for speed
ing up the return movement of the depressed
key lever, it has been already proposed to provide
the displacement pawl with a wedge like surface
engaged by the teeth of the ratchet wheel or
verting escapements of conventional design into
my improved escapement.
Other objects and advantages of my inven
tion will become apparent from the following de
scription taken in conjunction with the accom
panying drawings, in which:
Fig. 1 shows an embodiment of my invention
including a vertical section of the key action and
illustrated the displacement pawl in its normal
rack under the influence of the carriage spring.
As a modification of the same principle it has
been also suggested to provide the ratchet wheel
Ul with teeth having an oblique or wedge like sur
or rest position;
Fig. 2 is a fragmentary View of the pawls and
ratchet shown in Fig. 1 illustrating the displace
ment pawl in its position when the type lever is
face which were engaged by a displacement pawl
of conventional design. Although these arrange
ments have been successful in speeding up- the
operation of the paper carriage and of the key
levers all escapements of this type had the com
mon disadvantage that frequently the paper car
riage would be displace d by several steps if the
operator was too slow in withdrawing his fin
ger from the depressed key. Of course, this cir
cumstance interfered seriously with the correct
operation of the typewriter confronting' the art
with a problem for which as far as I am aware
of no satisfactory solution has been offered.
I have discovered that it is possible to elimi
nate all of the aforesaid shortcomings of the
prior escapements and to provide a completely
satisfactory and reliable escapement device in
a remarkably simple manner.
It is an object of the present invention to pro
vide an improved paper carriage escapement for
typewriters which permits quick and easy dis
placement of the paper carriage and utilizes
part of the energy stored in the carriage spring
for the return movement of the key lever, type
40 lever, and the like.
It is another object of the present invention
to provide an escapeme nt device for typewriters
which embodies the advantages of wedge-like
surfaces in its co-operating parts and at the
the danger of unintended
movements of the paper carriage when the de
pressed key lever is released too slowly.
A further object of the invention is to incor
porate a safety catch into one of the co-operat
50 ing members of the escapement and thereby
insure easy and reliable displacement of the
paper carriage at all speeds or conditions oi’
' same time eliminates
operation.
The invention also contemplates an improved
ratchet which is provi ded with wedge shaped
depressed;
Fig. 3 is a similar view depicting the displace
ment pawl partly returned by the ratchet tooth
under the innuence of the carriage spring said _
pawl being locked by the safety catch due to the 20
key not being released yet;
Fig. 4 shows the displacement pawl in the last
part of its return movement;
Fig. 5 is a fragmentary View of a modified em
bodiment or" the invention depicting the position
of the displacement pawl when the type lever is
depressed;
Fig. 6 is a similar view illustrating the dis
placement pawl when the type lever has been 30
partly returned but the key is not released yet;
Fig. 7 shows the displacement pawl in its posi
tion of rest;
Fig. 8 shows another modiñed embodiment of
the invention;
Y
Fig. 9 is a fragmentary View of the pawls and »
ratchet shown in Fig. 8 depicting the displace
ment pawl in its position of rest;
'
Fig. 10 is a similar View illustrating the pawls
when one oi the key levers is depressed;
Fig. li shows the displacement pawl partly re- 'Ä'
turned and engaged by the safety catch on the
ratchet wheel tooth;
Fig. l2 is a somewhat fragmentary plan view
oi my improved ratchet wheel with safety catch;
Fig. 13 shows the assembly of my improved
ratchet wheel;
Fig. i4 is a iront elevational view, somewhat
fragmentary, of my improved ratchet wheel hav
ing a safety catch in co-operation with a con
Ventional displacement pawl; and
Figs. l5 and 16 show diagrammatically two
consecutive steps in the operation of the escape
ment illustrated in Fig. ifi.
According to the principles of the present in
vention, a novel combination is provided involv
50
2
2,108,112
ing a ratchet and an escapement pawl either of
which is provided with a wedge-like surface and a
safety catch.
The safety catch preferably has
a short angular surface which is preferably nor
mal or perpendicular to the direction in which the
teeth of the ratchet wheel are moving. This
angular surface will act as a safety catch and
will detain the ratchet wheel teeth momentarily
during its sliding off movement, if the depressed
10 key is not released fast enough.
In some cases,
I prefer to provide the displacement pawl or the
pawl carrier with a very light spring in order to
return the pawl or carrier to its normal position
of rest.
The principle of my invention can be also em
ployed in escapements of the type where the
wedge-like surface is on the teeth of the ratchet
wheel. In this case I add the angle surface or
safety catch to the teeth of the ratchet wheel,
which I provide with a short extension surface
preferably at right angles or normal to the
direction of movement of the ratchet wheel. The
practical results will be the same as when the
safety catch is applied to the displacement pawl.
I found that the latter modification is especially
adaptable to be used as an attachment or replace
ment part for typewriters of conventional design,
because the conventional ratchet wheel can be
easily exchanged and replaced with my improved
ratchet wheel provided with wedge-like teeth and
safety catch thereby improving the performance
of the typewriter quite considerably. Of course,
an old pawl in a conventional typewriter can be
replaced just as easily with a new pawl having a
Co Ul wedge-like surface and a safety catch as the
replacement of the old ratchet wheel.
Referring more particularly to Figs. 1 to 4,
ratchet wheel 7c is rotatably arranged between two
bearings Z and m and is provided with teeth d.
40 The ratchet wheel co-operates with a displace
ment pawl b integral with a pawl carrier t pivoted
at i and held in its normal position by spring h.
On the right side of pawl carrier t, a retaining
pawl p is mounted on a pivot 1' and held in its
45 normal or rest position by spring s. The dis
placement pawl b has a wedge-like surface c
which is provided at the end thereof with a safety
catch f. This safety catch is preferably arranged
at right angles to the direction of movement of
50 the ratchet wheel, as may be clearly seen from
Fig. 1.
The left side of Fig. 1 shows a conventional
key action comprising key lever K connected by
link L to front link M which in turn is connected
Link S is con
nected at one end to member O rigidly fastened
to link N and at its other end is hooked around
the universal bar u. The type lever T is held
in its normal position by means of spring R and
60 strikes on platen P when actuated. The lower
55 by link N to the type lever T.
end of the pawl carrier t is provided with a re
siliently mounted little roller a which is ad
justable by means of screw o and is adapted to
co-operate with the universal bar.
The operation of the aforesaid embodiment of
my invention is apparent to those skilled in the
art. When key lever K is depressed, through
link L, front link M and link N the type lever
T will be actuated and will strike against platen
P. At the same time link S will pull the univer
sal bar u, to the left which in turn will engage
roller a and actuate pawl carrier t. This will dis
place escapement pawl b so that its wedge shaped
surface c will rest on or will engage the ratchet
tooth d as may be seen in Fig. 2.
At the same
time the detaining pawl p will release the ratchet
wheel and consequently tooth d under the in
fluence of the carriage spring will move in the
direction of the arrow along and in contact
with the wedge-like surface c of the displace
ment pawl b. This action will cause the displace
ment pawl b to move out of its path until the
ratchet tooth d with its surface e >abuts the safety
catch f as depicted in Fig. 3. The pawl carrier t
and the displacement pawl b under the influence
of spring it will continue their return movement
as soon as the depressed key is released and they
will return to their normal position of rest. In
this return movement, the pawl is assisted by hav
ing safety catch f sliding off surface g of the
ratchet tooth. .
Referring now to Figs. 5 to '7, they illustrate
my improved wedge-like displacement pawl in
co-operation with a ratchet wheel of conventional
design having rectangular teeth d--2. In view
of the similarity of construction, the description
will not have to be repeated and similar refer
ence characters are used to denote parts identical
with those appearing in Figs. l to 4. The opera
tion of this combination is similar to the one de
scribed hereinabove and will be readily under
stood from the drawings showing the escape
ment in successive phases of its operation. The
only difference is that due to the rectangular
shape of the ratchet teeth :1_2 the displacement .f
pawl will be returned to its normal position of
rest immediately after the depressed key has
been released.
It is to be observed that the escapement oper
ates in the described manner only when the key is .
allowed to return slowly to its normal position of
rest. When typing fast, the displacement pawl
will be returned completely to its normal posi
tion of rest in one movement due to the ñrst
impulse exercised by the ratchet tooth on the
wedge surface of the displacement pawl.
In the other embodiment of my invention il
lustrated in Figs. 8 to 13, a safety catch is in
corporated in each wedge-like tooth of the ratch
et wheel which co-operates with pawls of con
ventional design. Similar reference characters
are used in Figs. 8 to 13 to designate parts iden
tical with those described hereinabove and illus
trated in Figs. l to 7. Ratchet wheel lc-l is
provided with wedge-like teeth d-l having a
surface g-L At or near the end of each tooth, 50
a catch _?-l is incorporated which is preferably
at right angles to the direction of rotation of the
ratchet wheel. Displacement pawl b-l and pawl
carrier t-l which are integral, are pivoted at
i-l and the displacement pawl is capable of 55
engaging the teeth of the ratchet wheel and
particularly safety catch f-l.
The retaining
pawl p_l is pivotally arranged in the con
ventional manner on pawl carrier t-L
Figs. 8 and 9 show the pawls in the normal
position of rest. When a key is depressed link
s_l will displace the universal bar u_l to the
left so that this will strike against screw v-I
and will actua-te the pawl carrier t-l. The end
60
of the displacement pawl b-l will rest on or 65
will be in contact with the wedge shaped surface
g-l of tooth d-l as may be seen in Fig, 10.
At the same time the retaining pawl p-l will
release the ratchet wheel so that tooth d-l
under the influence of the carriage spring com
municated through the rack œ and gear y will
move in the direction of the arrow. This will
move pawl b-l in the direction of its normal
or rest position until it engages or abuts the-
3
2,108,112
safety catch f-l as may be seen in Fig. 11. In
this manner, the escapement will be locked in
ed to co-operate with the sliding off displace
this position momentarily and unintended dis
placements of the carriage will be impossible be
fore the key is completely released.
I have found that when manufacturing ratchet
wheels embodying the principles of my inven
tion, it is the simplest to make them from two
pieces which are subsequently rigidly connected
to each other. An improved ratchet wheel made
ment wall to retain and lock the ratchet wheel
until the complete release of the depressed key.
2. An escapement dveice for typewriters com
prising a ratchet Wheel having a plurality of
teeth bearing bevel surfaces, a detaining pawl
adapted tol engage a tooth of said ratchet wheel
in its normal position of rest and to release same
with this method may be seen in Figs. l2 and
13. Part o of the ratchet wheel carries the
wedge-like teeth and part n the safety catches.
After these parts have been made up separately
and brought in the correct position in relation to
each other, they are rigidly united by means of
screws, rivets or the like.
My improved escapement permits the insertion
of a resilient member between the universal bar
and the pawl carrier of any typewriter. Of
course, the resilient member will have a suit
able construction so as to displace the pawl car
rier from its position of rest when one of the
keys is depressed. This construction produces
25 an easy and elastic touch and has a tendency to
speed up the return movement of the type lever.
In addition, the escapement operation proper
will be much quicker and smoother because the
carriage spring will exercise greater force on the
30 wedge surface than the associated resilient mem
ber or buffer spring.
Fig. 14 shows my improved ratchet wheel em
bodying a wedge-like surface and” safety catch
in co-operation with a conventional escapement
35 similar to that of the well-known Royal type
writer. Fig. 14 closely resembles the escape
ment illustrated in Fig. 8, the displacement pawl
22-2 being provided with a small ball w rotatably
mounted at the end of the displacement pawl.
Similar reference characters have been used both
40 in Fig. 8 and Fig. 14 to denote identical parts.
It is believed that the construction and oper
ation of this particular embodiment of my in
vention will be readily understood by those skilled
in the art from the foregoing description given
45 in connection with Figs. 8 to 11.
Figs. 15 and 16 are fragmentary and diagram
matical views of two successive phases in the
when actuated, a displacement pawl capable of
slidably receiving said disengaged tooth, means
for actuating said pawls during the forward
stroke of a type lever, and a short safety catch
surface for each tooth of the ratchet wheel ad
joining the said bevel surface towards the dis
placement pawl substantially at right angles to
the path of said tooth, said safety catch surface
being adapted to engage the sliding off displace
ment pawl and to detain and to lock said ratchet
wheel until the complete release of the depressed
key.
15
20
~
3. An escapement device for typewriters hav
ing keys comprising a ratchet wheel having a
plurality of teeth bearing angular surfaces, a
pawl carrier adapte-d to- receive impulses from the
forward stroke on the keys of said typewriter, 25
a detaining pawl mounted on said carrier and
adap-ted to engage a tooth of said ratchet wheel
in the normal position of rest of the pawl carrier
and to release same when said pawl carrier is
actuated, a displacement pawl on said carrier 30
adapted to slidably receive said -disengaged tooth,
resilient means for maintaining said carrier and
said pawls in their initial position, and a short
safety catch surface for each tooth of the ratchet
wheel adjoining the said angular surface towards
the displacement pawl substantially at right
angles to the path of said tooth, said safety catch
surface being adapted to engage the sliding off
displacement pawl and to- detain and to lock said
ratchet wheel until said carrier and said~key are
completely released.
4. In a ratchet wheel for typewriter escape
ments, the improvement which comprises a cir
cular member having a plurality of teeth each
bearing an angular surface, a second circular 45
member Vhaving identical number of teeth at
right angles to the plane of said members and
adapted to form extensions for said angular
operation of this escapement. Fig. 15 depicts teeth, and means for rigidly connecting said
50
the position of the retaining pawl and of the circular members to each other.
5. An escapement device for typewriters corn
50 displacement pawl in relation to the tooth of the
ratchet wheel when the key lever is actuated, prising a powered ratchet wheel having teeth, de
while Fig. 16 shows the pawls in their locked taining and displacement pawls adapted to en
gage one of said teeth at a time and having sur
position when the key lever has not been com
55
55
pletely released yet.
I claim:
faces co-operating with corresponding surfaces
, on said ratchet wheel teeth, at least one of said
co-operating surfaces being at an angle other'
than right angle to the direction of movement of
said ratchet wheel, means for actuating said
60
pawl adapted to engage a tooth of said ratchet pawls during the forward stroke of a type lever
to permit movement of said ratchet wheel by one
60 wheel in its normal position of rest and to re
lease same when actuated, a displacement pawl tooth, and a safety catch surface adjoining said
slidably receiving said disengaged tooth, means angle surface and at substantially right angles
for actuating said pawls during the forward to> the direction of movement of said ratchet
wheel capable of locking the other col-operating
stroke of a type lever, and a short safety catch
surface after the forward stroke of the type lever
65 surface for each tooth of the ratchet wheel ad
depressed key.
joining the said bevel surface substantially at until the complete release of the
FRITZ EIBERT.
1. An escapement device for typewriters com
prising a ratchet wheel having a plurality of
teeth provided with bevel surfaces, a detaining
right angles to the path of said tooth and adapt
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