Improvements in Apparatus for Indicating the Speed of Revolving Shafts and the like.
Year: 1890

page_text: Date of Application, 22nd Feb., 1890
Complete Specification Left, 22nd Nov., 1890-Accepted, 27th Dec., 1890
PROVIDIUNAL SPECIFICATION.
Improvements in Apparatus for Indicating the Speed of Revolving
Shafts and the like.
I, THEODOR HORN, Doctor of Philosophy of No. 30 Elisenstrasse, Leipzig, in the
Empire of Germany, Manufacturer, do hereby declare the nature of this invention
to be as follows:-
The object of this invention is a device for indicating at a distance through an electric
current the revolving speed of shafts engines and such like.
The improved device consists of two electrically connected principal parts, one of
which is placed near and actuated by the respective machinery or shaft, while the
other is adapted to indicate the number of revolutions on a dial.
The first named or working portion embodies in addition to a contact mechanism
a comic-pendulum tachometer, which denotes the number of revolutions within the
engine room. The indicator or hand device of said tachometer is connected through
a rod with a driver or sector actuating by means of transmission wheels a contact
roll or cylinder which revolves in the one or other direction according as an increase
or decrease of speed takes place. On the shaft of the contact cylinder a brass tube
is so mounted as to be insulated therefrom and to receive the electric current from a
slide spring connected with the battery pole. The cylinder carries four contact disks
on which slide springs connected with as many pole screws.
Each of said disks has six metal segments which are in conductive connection
with the brass tube referred to. The interstices between the said segments
are filled with insulating material and have double the width of the segments. The
relative position of the latter on the contact disks is such as to cause the current to be
alternately directed into four conducting wires leading to the indicator proper while
the return conduit for the currents is formed by the wire connected with the slide
spring of the brass tube. The four currents incite alternately four horeshoe-shaped
electromagnets provided in the indicator proper which impart a corresponding oscillating
movement to their pivoted armatures.
This movement is converted into a rotary movement of a small crank by means of
two slotted arms or through interposed light drawing rods. The iron cores of the
electromagnets are tubular and longitudinally slotted, while the armatures are made
from thin sheet metal to allow of a rapid incitation and disappearance of
magnetism.
The motion of the crank is converted by means of toothed gear into slow motion and
transmitted to the dial shaft.
The currents passing through the four electromagnets unite on a brass plate and flow
through a conducting wire to a coil having an action similar to that of a galvanoscope,
except that, instead of a band, a kidney-shaped disk is moved which carries letters indi-
cating "forward" and "backward" and appearing in the respective recess of the dial
according as the machinery is working forward and backward. From the said coil
the electric current returns through the respective wire to the source of electricity.
The latter is in the present case supposed to be a magneto-electric machine, the
armature or drum of which is mounted on the main shaft of the working apparatus,
while an ordinary battery suffices as source of electricity where a forward or back-
ward working is not to be indicated.
In the latter case the movement of the machinery may also be transmitted to the
indicator proper by means of two conducting wires only and a common return conduit,
two electromagnets being then employed, while two spiral springs are substituted for
the two other electromagnets. Said springs tend to turn the armatures of the two

page_text: electromagnets in the same direction as the incited omitted electromagnets
would do.
The contact cylinder has in this case only two contact disks the conductive segments
of which have equal width with the insulating interstices.
Dated this 92nd day of Fahr 1800
COMPLETE SPECIFICATION.
Improvements in Apparatus for Indicating the Speed of Revolving
Shafts and the like.
I, THEODOR HORN, Doctor of Philosophy of No. 30 Elisenstrasse, Leipzig in the
Empire of Germany, Manufacturer, 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 improvements in apparatus for indicating the speed of
revolving shafts and such like by means of electric current.
All of the known apparatus for indicating at a distance degrees of temperature
level of water and the like, in which the electric current serves as an agent for trans-
mission of motion are inadapted to indicate in a reliable way the revolving speed of
engines or shafts. If, for instance, the speed of a marine engine is to be indicated
on the captain's stand by means of a distance indicator, the apparatus must be capable
of so rapidly following the fluctuations of velocity as to cause also on a sudden
transition of the engine from the forward to the backward motion,-the instrument
placed on the captain's stand or bridge to assume at any moment a position corre-
sponding to the speed of revolution at the time being.
Reference being had to the accompanying drawing, in which like letters denote like
or corresponding parts, A is an apparatus, which is destined to be placed by the side
of the engine whose speed of revolution is to be indicated, said apparatus being
actuated by the engine. Another apparatus B which forms with A the improved
indicator is adapted to show at the remote point the number of revolutions on a dial
plate.
Figs. 1 and 2 illustrate a contact work which forms part of apparatus A.
The
The other part of the latter consists of a conical pendulum tachometer (omitted in
the drawing) which indicates the number of revolutions in the engine room and from
the hand device of which a rod s Figs. 1 and 2 leads to the rack r. The latter drives
by means of transmission wheels the contact cylinder W, which, when the velocity
increases moves in the direction indicated by arrows in Figs. 1 and 2. Over the shaft
of the contact cylinder is shifted a brass tube m insulated therefrom. The current is
transmitted to said tube through a slide spring connected with the pole screw e. On
the brass tube are provided four contact plates which with the springs sliding thereon,
and the appurtenant pole screws are lettered a b c d Fig. 2. Each of these plates
has six metal segments, which are in conductive connection with the brass tube m.
interstices filled up with insulating material have double the width of the segments.
The relative position of the latter on the four contact plates is such that they
alternately transmit the current to the four wires a¹ b c d leading to the apparatus B.
The wire e serves as return conduit. These currents excite in apparatus (Figs. 3
and 4) alternately the four horseshoe-shaped electromagnets a¹ 61 c¹ d¹ which give
the appurtenant armatures, revoluble about shafts g and h, a corresponding oscillating
movement, Fig. 5. The latter is converted by means of the slotted arms i and k into
a revolving movement of the small crank C, or also (Fig. 6) transmitted by the insertion
of light draw rods and k¹ to C. The iron cores of the electro magnets are tubular
and slotted longitudinally while the armatures are made from thin sheet metal to allow
the magnetism to rapidly generate and varnish.
The movement of crank C is reduced by means of toothed wheels and transmitted
to the hand shaft z. Also the arrows shewn in Fig. 3 correspond to the direction of
movement of the corresponding parts when the velocity of the engine is increasing.

page_text: The currents returning from the four electromagnets a b c d¹ unite on the brass
piece n Fig. 3, and pass through wire e² to a wire spool G, which operates in a similar
manner as in the galvanoscope, except that a kidney-shaped plate S is moved in lieu
of the band, on which plate are provided letters "V" and "R" indicating respectively
forwards and rearwards. On the backward movement of the engine the letter V
appears in the round cut of the dial plate (Fig. 3). From spool G the current returns.
through e and e' to the source of electricity Q. The latter is in this case supposed to
be a magneto-electric machine, whose armature or drum is attached on the main shaft
of the apparatus A. In those cases in which a forward or rearward motion of the
engine is not to be simultaneously indicated also an ordinary battery suffices as source
of current.
To allow the co-operation of the contact plates a bed and of the electro-
magnets a b c d to be more easily controlled, the relative position of the metal
segments of the contact plates is schematically illustrated by Fig. 7. The shaded
rectangles denote the metal segments. The contact cylinders are supposed in
Fig. 7 to be wound off into the plane and are accordingly lettered a b c d. The lines 1,
2, 3, 8 running in the direction of the metal lines of these surfaces indicate
the contact springs in eight different positions. The corresponding eight positions of
crank C are indicated by eight radii of circle C. The contact cylinder W is supposed
to be so adjusted, that when the engine is at rest, the slide-springs slide on the discs
along line 1, so that disc a and the electromagnet al are in conductive connection.
Supposing the crank C occupy the position 1 (Fig. 7), the swinging pendulum in A
were so arranged as to make up to 25 "dead revolutions" and that only when this
number of revolutions is exceeded, the hand mechanism were set in motion.
When the engine, or the apparatus A, makes less than 25 revolutions, the contact
cylinder W is not yet set in motion and the current following through a and a¹ will
hold the crank C in position 1. Only the disc S is deflected to the right so that the
letter V appears in the cut of the dial plate of B. When the. speed of the engine
increases to more than 25 revolutions, the contact cylinder W is set in motion in the
direction indicated by arrow Fig. 1, the contact line of the slide springs occupying
with regard to the segments of the contact cylinder successively the positions 2, 3 .....
Fig. 7.
In position 2, the contact plates a and d are in conductive connection with the
appurtenant wires a' and d and consequently the magnets a' and d¹ of apparatus B
are excited. a' attracts h and therefore tends to maintain the crank pivot y in
position 1; at the same time attracts 7 and tends to move the crank into position 3,
the resultant position being 2.
When the contact line of the slide springs advances into position 3, only the disc d
engages the current, and magnet d' only is excited, consequently the crank Cassumes
position 3. When the contact line advances further into the position 4, 5.
the corresponding magnets in apparatus B so co-operate as to cause the crank to
assume the respective positions 4, 5, . To à revolution of cylinder W for a
segment correspond eight consecutivo positions of crank C or one full revolution of
the same.
When therefore the contact cylinder makes a whole revolution, the
crank runs through 48 consecutive positions. The hand of apparatus B con-
sequently advances by small sections and precisely indicates minor fluctuations of
velocity.
When the speed of the engine decreases the contact cylinder moves backward and
the crank C runs in inverse succession through the abovementioned eight positions,
while a dead travel can occur at the crank when the revolving direction of the contact
cylinder is changed. With the decrease of the speed of the engine up to 2 revolutions,
the hands A and B reach their starting position, which they continue to occupy on
further decrease of speed. The plate S of apparatus B however presents the letter V
as long as current passes through the conduit in the directions indicated by arrows
that is to say as long as the engine has not quite ceased to move forward.
As soon as the engine (for instance a marine engine) begins to run backwards, the
direction of the current is reversed. The plate S turns to the left and shows in the

page_text: The reversin
of the direction of
cut of the dial plate the latter R (backwards).
current however has no influence on the position of the hand in the apparatus B; the
latter moves precisely the same as with the forward movement provided the same
changes of speed prevail.
It an advance or rearward movement of the engine is not to be indicated and the
velocity of the engine connected with the apparates changes but slowly, the trans-
mission of motion of the hand mechanism may also be effected-with the retention
of the swinging armatures g and h and of the crank C-by means of two wires only
and a joint return conduit. In such a case only the two electromagnets b' and c¹
(Fig. 3) are employed and the magnets a¹ and d' are replaced by two spiral springs,
which tend in the same manner to turn the armatures g and has the excited
magnets a and . On the contact cylinder W are mounted two contact discs only,
the conductive segments of which are equal in width to the insulating interstices. Said
discs must occupy such position relatively to each other that, by the slide springs b
and c, the current is so conveyed to b¹ and c¹, that when the cylinder W is turned for
one contact piece, the following four cases will consecutively ensue.
current however has no influence on the position of the hand in the apparatus B; the
latter moves precisely the same as with the forward movement provided the same
changes of speed prevail.
It an advance or rearward movement of the engine is not to be indicated and the
✓ velocity of the engine connected with the apparatus changes but slowly, the trans-
mission of motion of the hand mechanism may also be effected-with the retention
of the swinging armatures g and hand of the crank C-by means of two wires only
and a joint return conduit. In such a case only the two electromagnets b¹ and c
(Fig. 3) are employed and the magnets a¹ and d¹ are replaced by two spiral springs,
which tend in the same manner to turn the armatures 9 and has the excited
magnets a and . On the contact cylinder W are mounted two contact discs only,
the conductive segments of which are equal in width to the insulating interstices. Said
discs must occupy such position relatively to each other that, by the slide springs b
and C, the current is so conveyed to b¹ and c¹, that when the cylinder W is turned for
one contact piece, the following four cases will consecutively ensue.
1.) Neither & nor c,
2.) 6 only,
3.) b and
4.) c only,
will transmit current to the conduit. To these four cases correspond the positions of
crank indicated in Fig. 7 with 2, 4, 6 and 8.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :
In an apparatus for indicating the speed of revolving shafts and the like.
1) The mode of transmitting the movement of a dial mechanism and of a contact
cylinder W of an apparatus A to an apparatus B by means of four wires and a joint
return conduit in such a manner, that the currents which flow alternately through the
four wires excite four electromagnets, each two of which impart to one of the
armatures and a reciprocating movement which is transmitted to a crank C by
means of slotted arms i and k, the relative position of the contact pieces on the
contact plates a b c d corresponding to the scheme shewn by Fig. 7. substantially as
set forth.
2) The manner of transmitting the movement of the dial mechanism of the
apparatus A to the apparatus B through two wires and a joint return conduit in such
a manner, that on each of the armatures g and h acts an electromagnet in one and a
spiral spring in the opposite sense with such a degree of energy that by the magnetism
generating and vanishing the armatures and are given an oscillating movement,
the relative position of the contact pieces of the two contact plates to be provided on
cylinder W corresponding to above description, substantially as illustrated and
described.
Dated this 21st day of November 1890.
1033.
THEODOR HORN.
Per Huelser & Co.,
Temple Chambers, London, his Agents.