Improvements in Electrical Selecting Instruments.
Year: 1896

page_text: Date of Application, 1st Sept., 1896-Accepted, 26th Sept., 1896
COMPLETE SPECIFICATION.
[Communicated from abroad by JOHN MOWE DRYSDALE, of New
York, U.S.A.]
Improvements in Electrical Selecting Instruments.
1 THEODORE MCKENNA of 17 and 18 Basingball Street in the City of London
Solicitor and 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:-
This apparatus is an improvement upon instruments known as electrical
selecting instruments, and is provided with devices responding to a fixed com-
bination of impulses whereby any one of a number of instrumentalities may be
picked out or selected upon a given line and the particular features of the present
improvement relate to parts which make the selector more accurate and perfect
in its action.
The accompanying drawings illustrate the invention of which
Figure is a side view of the instrument with one of its supporting walls
removed, taken on line 2-2, Figure 2 looking in the direction of the arrows.
Figure 2, a top or plain view of the instrument.
Figure 3, a perspective view of the operating parts of the instrument.
Figures 4, 5, 6, and 7 are views of the combination wheel and guardian wheel
in different positious illustrating the operation of the instrument when operated by
a true combination and also when a false combination is attempted.
Figure 8 is.a view of the actuating pawl showing its operating edge, shortor as
applied to the combination wheel than on the guardian wheel.
Figure 9, a view showing the inclined plane with projection on pawl riding
thereon.
The standards or side-walls A are erected upon a suitable base and support the
operating mechanism of the selector.
Upon a shaft B suitably journalled in the frame is mounted the combination
wheel C. This shaft is provided with a spring which may be coiled and placed
within the drum c, which exerts its tension against the impelling pawls and
restores the selector to zero at the proper time.
The entire combination is cut mechanically on the periphery of this wheel, and
is.represented thereon by deep and shallow notches whose purpose will be more
fully explained hereafter, and when the true and correct combination of impulses
is received by this selector from a transmitter, the ontiro combination may be
worked out upon this single wheel, the instrument brought to the end of its phase
by a current in a single direction transmitted through the coils of a single magnet
actuating a single armature lever, or the same operation may be performed by
hand.
D is an electro-magnet of the usual form, d' an armature lever, and da
pawl pivoted to the lever to co-operate with the combination wheel and
impel it to work out the phase of the instrument, the pawl is provided
with the usual spring, whose tension is exerted to hold the actuating or
free end of the pawl against the periphery of the wheel. It is also provided
with a projection d' which slides upon the inclined plane d and throws
the pawl out of contact with the wheel at proper times, thus preventing
impulses from the transmitter which actuate the armature of the electro-maguet

page_text: As the
from turning the wheel as will be more fully explained hereafter; in this conuection
there is a retarding device connected with the instrument and a provision for lost
motion which comes into play and performs functions which assist in the proper
working out of the phase of the instrument. The retarding device consists of the
ratchet wheel E and anchor el connected by means of pinion e', rack e, pine and
arm with the armature lever d¹ and serves at the proper time to retard the
movement of the lever; the arm e is slotted as shown at e and within this slot
the pin on the rack-armn cuters and plays therein sufficiently to accomplish its
purpose. Returning to the inclined plane d and the projection on the operating
pawl, it will be seen, that these devices are adjusted with each other in a way
to secure proper co-operation, which may be explained as follows: The inclined
plane is pivoted at d, its spring de, draws the upper end inwardly until stopped by
the set-screw, where it remains held, it may have a slight movement outwardly
at the top but when such movement is made it returns again to its set position.
When the armature lever is up to the limit of its backward stroke the parts are
in the position shown in Figures 1 and 3, with the projection d, above the upper
end of the inclined plane; when the armature lever descends this pawl passes
insido of the inclined plane to propel the wheel, or outside to slide upon the
plane, throw out the pawl, prevent it from impelling the wheel, and leave it
standing still, and these functions are effected by the position which the free end
of the operating pawl occupies to the combination on the wheel.
combination is mechanically represented on this wheel by deep and shallow
notches in its periphery, the projection and inclined plane d' are so arranged
with each other that when the end of the pawl is in a deep notch and descends, its
projection passes inside of the inclined plane and the pawl propels the wheel;
but if the pawl is in a shallow notch or on a space between the notches the
projection will, in descending pass outside and sliding down upon the inclined plane
throw the pawl out of contact with the wheel, provided that when it starts its
descent, the projection is above the end of the inclined plane, hence upon this
wheel the shallow notches are arranged close to each other or a shallow notch is
arranged closely behind a deep one, and the transmitted impulses which operate
upon the shallow notches are given quickly to be sure that the pawl in returning
to take hold of a shallow notch shall not return far enough to pass the end of the
inclined plane, and thus may continue to work upun the shallow notches by
reciprocating wholly inside of the inclined plane; between a shallow notch and a
deep one there is a space which allows the pawl to go further back and in this case
although the projection passes beyond the end of the inclined plane, yet in
descending it will pass inside owing to the deep notch which allows the parts to
escape. From this it will be seen that this single wheel may be operated to the
end of its phase by the trausmissious of impulses having long and short intervals
between them and operating a single armature lever.
On the shaft of the combination wheel is placed a crank, which turns with the
wheel and controls a circuit by acting upon the brushes b, b, to open or close them,
as the case may be, and when this occurs the selector has completed its phase and
is ready to be returned to zero. There is also placed on the instrument a stop d
which limits the downward throw of the armature lever so that in each instrument
the armature begins its return movement from a fixed position, being the end of its
downward stroke. In the operation of the instrument an independent cheoking
device is provided and the lost motion in the parts bereiubefore described performs
its service.
Pivoted to a suitable part of the framework is the check pawlf, with its spring
to hold it against the wheel, and from the rack e projects the pin et which comes
against the inner side of the pawl and throws it out when the armature lover
returns backwardly. When the armature is down the check pawl is always in place,
checking the wheel and the armature may return back to the distance travelled by
the pin in the slot; within this distance the armature may return to allow the
actuating pawl to take hold of a shallow tooth without passing the projection

page_text: beyond the end of the inclined plane, and thus reciprocate to work the wheel, but
if the projection passes above and gets outside, it may slide up and down in
response to the impulses within the distance of the lost motion without throwing
out the check pawl, and thus leave the wheel standing still; when once out, should
it go back far enough to pass within it will either drop into a deep notch or else
go back and throw out the check pawls releasing the wheel whose spring returns it
to zero.
In the construction of selecting instruments a trouble has been encountered which
is known among skilled mechanics as "creeping over," that is to say, with instru-
ments which work upon a combination and employ a current of a single polarity, a
combination may be worked out properly upon a selected instruinent and yet on lines
where many impulses are transmitted some one of the other instruments may be set
off by "creeping over" its course, and to prevent this, I have combined with the
combination wheel another wheel; the two wheels are separately and independently
mounted upon the shaft, have separato and independent movements forward and
backward but both are worked by the same armature lever and the same actuating
pawl; they work together in unison so long as the proper combination is sent out,
but when a false movement is given by the actuating device, this second wheel
ad vanecs whilst the other stands still, and coming to the end of its course first
operates the devices which throw the combination wheel back to the and of its
course, thus preventing it from creeping over; this wheel is therefore a movable
restoring device and its function is to look after and protoct the combination wheel
and prevent it from creeping over, it may therefore be called a guardian device or
wheel.
Let us suppose that the entire combination of any instrument is represented by
sixteen impulses, hence within this combination there must be sixteen notches or
their equivalent in notches and spaces, that is to say, if an impulse bo represented
by a given length on the periphery of the wheel, then, on the combination wheel
there would be represented 44 notches, or spaces and notches, as will be seen by
viewing Figures 4 and 5, first there are sixteen of the 44 parts taken up in the
combination proper, which consist of deep and shallow notches separated by spaces
of varying lengths, such notches and spaces may be called the members of the
combination, then follows a space equal to 6 notchos, then a ratchet of fifteen
teeth, then a space equal to seven teeth; and the other wheel has the same
arrangement with a slight variation; it begins with 16 ratchets occupying the
space of the combination on the other wheel; then follows a space equal to six
ratchets, then follows 15 ordinary ratchet teeth, and an additional sixteenth tooth
slightly indented and not so deep as the others, and then a space equal to six teeth
completing the full number of 44. The number of 16 impulses representing the
combination is not obligatory, there may bo any number.
Both wheels are set upon the shaft in unison with each other and perform their
functions as follows:
If the true combination of impulses and spaces are transmitted for a given
selector, both wheels start from the position shown in Figure 4, with the pawl on
the combination wheel in a deep notch at the beginning of the combination and the
other side of the pawl resting in a tooth on the guardian wheel, and the check pawl
resting on the space 6, near the end and ready to drop into the notches on both.
wheels as soon as they are propelled. Both wheels work together arriving at the
end of the combination in the position shown in Figure 5; at this point the circuit
is closed or opened as the case may be and the work of the instrument performed,
when it is only necessary to allow the armature to go back and lift the check pawl
to restore the instrument to zero; but in other instruments on the line a false
impulse or space has been given during the operation of this instrument and these
are prevented from creeping over as follows: The actuating pawl is cut out a
little on the part which works the combination wheel as shown at d, Figure 8, 80
that it is a little shorter than the other; at the same time the check pawl is a little

page_text: shorter on the combination wheel than on the other; now it is evident that when
short'impulses are transmitted with short spaces between them, where a long space
ought to be made, the pawl may still travel inside of the inclined plane, part of it
riding on the space on the combination wheel without turning it, whilst the other
side of the pawl would continue to turn the other wheel which would advance out
of its relative position with the combination wheel as illustrated in Figure 6,
which shows the guardian wheel at the end of its course with its longer check pawl
in the shallow notch, leaving the check pawl on the combination wheel free from
the notchies.
Now in this position the armature returns and on the guardian wheel its pawl
rides upon the space marked 6. This action throws out the actuating pawl from
the combination wheel, and as its check pawl is already thrown out, leaves the
combination wheel in the position shown in Figure 7 free to be returned to zero
by its spring. Thus the combination wheel can never be brought to the end of its
phase unless the exact counterpart of its combination is transmitted, as the pro-
jection will either travel on the inclined plane d', leaving it standing still until
returned by the backward throw of the armature or else the guardian wheel will
be advanced ahead of the combination wheel until it arrives at the point where its
action in co-operation with the actuating pawl will return the combination wheel
to starting point.
When the combination wheel has been returned to starting point as above
described and the actuating impulses from the transmitter have cease 1, the armature
is drawn back by its retractile spring, and actuates the releasing devices which
restore the guardian wheel to zero.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1. In a selecting instrument a movable phase-completing device adapted to
respond to a fixed combination of electrical impulses from a transmitter, and
provided with notches, in combination with an electro-magnet, and its armature
lever, and provided with an actuating pawl arranged to co-act with the notches in
the phase-completing device, means actuated by a false impulse to throw the pawl
out of the notches, and means for retaining the phase-completing device when the
pawl is thrown out.
2. In a selecting instrument a movable phase-completing device adapted to
respond to a fixed combination of electrical impulses received from a transmitter,
and provided with a series of deep and shallow notches constituting a mechanical
representation of the fixed combination of electrical impulses, separated by spaces
differing in length, in combination with an electro-magnet provided with an
armature lever responding to the impulses to thereby work out the combination,
and means governed by the length of the pauses hetween the impulses to allow the
armature lever to reciprocate without impelling the phase-completing device when
a false impulse is transmitted.
3. In a selecting instrument a movable phase-completing device adapted to
respond to a fixed combination of electrical impulses received from a transmitter,
and provided with a series of deep and shallow notches constituting a mechanical
representation of a fixed combination of electrical impulses, the shallow notches
separated from each other by a short space representing the pause between short
impulses and the deep notches separated from the shallow ones and from cach
other by a longer space representing a longer pause between the impulses, means
for working out the combination controlled by the length of the pauses between
the impulses, and means for preventing the phase-completing device from turning
when a pause of false length is made between two impulses.
4. In a selecting instrument a inovable phase-completing device adapted to
respond to a fixed combination of electrical impulses received from a transmitter

page_text: and provided with a series of notches separated by spaces in combination with an
actuating pawl co-operating with the notches to impel the phase-completing
device to the end of its course when the proper combination of impulses is
transmitted, and to ride upon the spaces between the notches without impelling the
phase-completing device when a false impulse is transmitted, and means for
retaining the wheel in position whilst the pawl is riding on one of the spaces.
5. In a selecting instrument a movable phase-completing devico adapted to
respond to a fixed combination of impulses received from a transmitter and
provided with a series of notches separated by spaces, in combination with an
actuating pawl co-operating with the notches to impel the phase-completing
device to the end of its course when the proper combination of impulses is
transmitted, means for throwing the pawl out of the notches when a false impulse
is transmitted, an inclined plane to receive a projection from the pawl and slide
thereon when the pawl is thrown out, and means for retaining the phase-completing
device in position whilst the pawl is sliding on the inclined plane.
6. In a selecting instrument n movable phase-completing device provided with a
series of deep and shallow notches representing a mechanical combination
composed of members, said members separated from each other by spaces differing
in length, in combination with impelling mechanism therefor to co-operate with
the notches and thereby impel the phase-completing device to the end of its
course, said impelling mechanism having a fixed and limited advance movement
and three backward movements, viz.: a short one for a shallow notch, a longer
one for a deep notch, and a still louger one to return the selector to zero.
7. In a selecting instrument a movable phase-completing device and actuating
mechanism therefor in combination with a movable, restoring device actuated by
the same mechanism and meaus for controlling the same brought into action by a
false movement of the actuating mechanism to thereby restore the phase-completing
device to zero.
8. In a selecting instrument a movable phase-completing device mounted upon
a shaft, and actuating mechanism therefor, in combination with a movable
restoring device mounted upon the same shaft and having an independent
movement thereon actuated by the same mechanism, menus actuated by a false
movement of said actuating mechanism to advance the restoring device without
advancing the phase-completing device.
9. In a selecting instrument a movable phase-completing device provided with a
series of notches separated by spaces, and constituting a mechanical combination
of members, in combination with a movable restoring device provided with a series
of successive notches or teeth, each of said devices being separately and in-
dependently movable, and an actuating mechanism therefor common to both
devices, means for holding the phase-completing device and advancing the
restoring device when the actuating mechanian is out of a notch on the phase-
completing device.
10. In a selecting instrument a movable phase-completing device provided with
a series of deep and shallow notches constituting a mechanical combination of
members each member separated by a space, in combination with a restoring
device having a separate and independent movement and both operated by the
eame actuating mechanism, means for throwing out the actuating mechanism
from the notches of the phase-completing device, means for holding the same,
and means for advancing the restoring device whilst the phase-completing device
is held.
11. In a selecting instrument a movable phase-completing device provided with
actuating mechanism therefor and devices for restoring the same to zero in
combination with a movable guardian device independently mounted and actuating
mechanism therefor, means for operating both devices in unison actuated by
working out the proper combination, or the impelling-mechanisin means for
operating the same out of unison when an improper combination is attempted, and

page_text: thereby advancing the guardian device to actuate the restoring mechanism of the
phase-completing device, and prevent it from completing its course.
Dated the 1st day of September 1896,
THEO. M'KENNA,
Applicant.