Improvements in Dynamometers.
Year: 1894

page_text: Improvements in Dynamometers.
I, RICHARD VOIGTLÄNDER of Gohlis near Leipzig in the Empire of Germany
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 means or apparatus for measuring mechanical work or
power in given periods of time.
An apparatus constructed according to this invention has two eccentrics arranged
in proximity to each other on a shaft or axle one being connected to a drum or
pulley mounted loosely on the shaft and the other being fixed on the said shaft.
One of these eccentrics is connected to the loose pulley by means of an elastic
medium such for instance as a helical spring or the like so as to produce by the
expansion and contraction of the said spring or the like a variable movement of
one of the eccentrics and transmit motion by means of a connecting rod to a
counting mechanism as will be hereinafter more fully described.
The apparatus may be applied to the crank shaft of an engine the pulley or
drum being mounted loosely on a prolongation of an eccentric nave or boss on the
said shaft. The elastic connecting medium as hereinbefore described may consist
of a helical spring placed inside a housing formed within the rim of the pulley and
the variable throw of the eccentric to operate the counting mechanism may be
produced by an arm on the said eccentric coming into contact with the spring.
Instead of the eccentrics I may employ two concentric metal discs one being
secured to the transmission shaft and the other being connected by means of a
spring to the loose pulley; one half of the periphery of each of these discs may be
insulated by any suitable hard material and on the periphery of one of the said
discs bears a suitably pivoted arm which serves (according to the relative movement
of these discs brought about by the power exerted) to make or break an electric
circuit. In this circuit is a suitable counting mechanism actuated by the electric
current and the extent of movement of the dial plates therefore depends on the
length of time the aforesaid arm is in contact with the metal surface of the one
disc.
And in order that my invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the
several figures on the annexed sheets of drawings the same letters of reference
indicating corresponding parts in all the figures.
Figure 1 of the accompanying drawings shows a front elevation and Figure 2 a
sectional elevation of one form of dynamometer constructed in accordance with the
present invention.
Figures 3 and are similar views to Figures 1 and 2 with certain parts removed
and Figures 5. 6. 7 and 8 are details.
Figures 9. 10 and 11 show in sectional elevation, side elevation, and plan
respectively the apparatus applicable to the crank-shaft of an engine and Figures 12
and 13 show enlarged sectional views of the counting mechanism.
Figures 14 and 15 show respectively in front elevation and sectional elevation at
right angles to Figure 14 a modification, and Figures 16 and 17 are respectively a
sectional elevation of the loose pulley detached, and a transverse section of the same.
Figures 18 and 19 show details of the two eccentrics.
A further modification is shown in front elevation & section in Figures 20 and 21
details of this form of dynainometer being shown in Figures 22, 23, 24, 25 and 26.

page_text: Figure 27 shows diagrammatically one method of communicating the variable
throw of the eccentric to a counting mechanism operated by electricity.
Figures 28. 29 and 30 show respectively in front elevation, section and sectional
plan another arrangement according to the present invention for operating the
counting mechanism by electricity without employing a connecting rod.
Figures 31 and 32 are details of the concentric discs employed in this modification
and Figures 33, 34 and 35 show the construction of the electric counting mechanism
drawn to a larger scale.
Referring to Figures 1 to 8 a is a pulley, which may if desired be in the form of
a toothed gear wheel or be constructed for rope driving and which runs loosely on
the shaft w: d is an eccentric fast on the said shaft w, and c is an elastic connecting
medium consisting of a spiral spring one end of which is connected to the nave of
the eccentric d and the other end by the pin to one of the arms of the pulley or
drum u.
On the eccentric d is placed an eccentric e the same being secured thereon
by screws 5, while other screws 6 secure the eccentric strap y to the eccentric e,
the said strap being the means of actuating by a connecting rod a counting
mechanism i. To the eccentric e is connected by a ping a collar (Figures 7
and 8) which is mounted so as to be capable of turning on the eccentric d and has
an arm b' which is connected to the pulley or drum a by means of the pin f, and
turus therewith, the pin g of the arm engaging in the slot 4 (Figures 1 and 5) of
the eccentric e. This arrangement admits of the eccentric e being adjusted with
reference to the eccentric d so as to alter the degree of eccentricity according to
the tension of the helical spring c.
If both eccentrics d & e are placed on the shaft with their throws dia-
metrically opposite each other the throw of the eccentric e becomes nullified and
no motion is given to the connecting rod z by the turning of the shaft w.
C
If power is exerted on the pulley or drum a the spiral spring c is contracted by
the peripheral force exerted, and as the spring is in connection with the
excentrics d and e. these are caused to move towards one another more or less
according to the force exerted on the pulley whereby the throw of the excentric e
is varied and consequently the movement through the connecting rod z of the
counting mechanism. The throw of the excentric is always proportional to the
force which contracts or expands the elastic medium. If the connecting rod z of
the eccentric e be attached to the lever h of a counting mechanism and the
leverage be arranged in such a manner that by a certain tension of the spring c
caused by the power exerted on the periphery of the drum a each throw of the
eccentric e operates a figure of the counting mechanism and if the peripheral force
exerted on the drum with each turn of the shaft be known then each figure of the
counting mechanism moved represents a whole definite product of distance moved,
revolution and peripheral force, so that each time the counting mechanism is moved
indicates the power exerted. The connection of the rod with the lever of the
counting mechanism may be so adjusted as to cause at each revolution of the shaft wo
one or more of the figures to be moved, or it may be adjusted so as to require two
revolutions of the shaft to move one figure of the counter.
The dynamometer may be arranged so that it can be applied to engines so as to
indicate the power exerted.
Figures 9 to 13 of the accompanying drawings shew the construction of the
apparatus for this purpose. In this case the pulley or drum a is free to turn upon
the protruding portion d' of the eccentric d (Figure 9) so that the apparatus can
be readily fitted on the shaft. In the example illustrated (Figures 9 to 11) the
apparatus is secured on the projecting end M of a crank shaft. The connecting
rod z is in this instance connected with an indicator q which indicates accurately
the output of the engine in horse power. The connecting rod is adjustably
attached to the lever k which communicates its reciprocating movement to the
toothed segments gearing with the small spur wheel (Figures 12 & 13). This
wheel is connected with the index finger u by means of a tube t and a helical
spring placed inside the latter. This index finger moves over the graduated scale

page_text: proportionately to the movement of the lever k and connecting rod 2 and so
indicates on the dial the power exerted.
In Figures 14 to 19 of the drawings a modification of the eccentric arrangement
is shewn. The two eccentrics are indicated by the letters de of which as in the
apparatus hereinbefore described e is connected by a pin f with the drum or pulley a
and by the connecting rod with counting mechanism the eccentric nave d being
secured on the shaft w. The elastic connecting medium is in the present case
placed in a housing within the drum a and consists of a helical spring c the
tension of which may be adjusted by means of the set screws 9 h. The eccentric
nave d is furnished with a lever d' the free end of which comes in contact with the
spring c the tension or expansion of which is thereby communicated to the nave d
so that the throw of the excentric e may be varied, the said throw being in turn
communicated to the counting mechanism as hereinbefore described. The variable
throw of the excentric e may also be effected by the following means:-
The hub or boss of the lever d' has an arm or lug k (Figure 23) which carries
by means of a pin the counter lever m (Figure 24); the said lever m has on its
arm the toothed segment 1 and opposite to this again the bifurcated arm 2 while
the eccentric e instead of having a circular hole to receive the transmission shaft is
provided with a slot (Fig. 25) and has moreover two eyes 3 & 4 which serve for
connecting the eccentric e with the bifurcated arm 2 of the counter lever m.
Figure 26 shews the combination of the eccentric e and counter lever m. The
pulley or drum a in this arrangement besides being provided with the housing b for
the spring c has the toothed segment piece n secured to it (Figs. 20 to 22).
Supposing now that all the parts are in the position shown in Figs. 20 and 21 the
lever being in contact with the spring c and the toothed segment 1 engaging
with the toothed segment piece n then when the spring c is compressed or extended
by a force (acting on the pulley a) the lever d¹ changes its position relatively to
the said pulley a or to the piece n provided upon the said pulley; simultaneously
the counter lever m is caused to change its position relatively to the shaft w by the
toothed segment 1 engaging in the segment piece n of the pulley and as the
eccentric e is connected with this lever d' it must also change its position on
the shaft thereby altering its throw and actuating the counting mechanism i
accordingly.
The variable throw of the eccentric of the dynamometer constructed in accord-
ance with this invention may be communicated in the most simple manner to an
electric counting mechanism. In the arrangement shown in Figure 27 the
connecting rod of the eccentric e is attached to a lever o one end of which as
shown in the drawing slides over contacts and transmits an electric current to the
counting mechanism p which is provided with a lever moving similarly to the said
lever o, but by suitable interposed gearing the dial plates of the counting mechanism
can only be moved in one direction, so that in this case the distance through which
lever o moves with each revolution of the shaft is greater or less according to the
variable power exerted on the periphery of the drum which shortens or draws out
the elastic connecting medium c the lever o of the counting mechanism p thus
moving the dial plates forward a distance depending on the force exerted.
In the
arrangement shown in Figs. 28 to 35 the two eccentrics d and e hereinbefore
described are replaced by two concentric discs d²e and the driving takes place
exactly as in the arrangements hereinbefore described by means of a pulley or
druim a connected by an elastic medium with a nave d which is secured on the
shaft w.
The concentric metal disc e³ which is capable of turning on the nave d
has its periphery covered with a ring ell of some suitable hard non conductor of
electricity in such a manner that one half of the said ring overlaps the disc d³
while on the other hand only a half of the circumference of the disc d is covered
with a like insulating material d".
The rings d" and ell are so disposed that if no force be exerted on the pulley the
whole periphery of the disc d is insulated, the uninsulated portion of the periphery
of the disc d being covered by the insulating material carried on the disc e². The

page_text: arm is secured to the disc e² and as in the hereinbefore described arrangement
(Figs. 1 to 8) is secured to the pulley a¹ by a pin f¹.
The concentric
On the disc d as well as on the projecting half of the ring e" bears a roller
which is connected with the lever g, the latter being free to turn on a fulcrum.
By this arrangement if the shaft w and the lever g are put into an electric circuit
where there is no power being exerted on the pulley, the lever g is completely
insulated by the two insulating rings d" and e" consequently the electric circuit is
broken. When force is exerted on the pulley the metal disc e² is turned by the
action of the arm 6' and with it the half of the insulating ring ell above the disc d'
before the shaft w is carried round by the electric medium c.
disc d² being secured to the nave d is first carried round therewith and by the
movement of the insulating ring ell above the disc d' a portion of the surface of the
latter will be uninsulated and by exposing the metallic periphery of the disc d² to
the roller on the arm g the circuit through the shaft w to the counting mechanism
will be established. The amount of the insulated portion of the periphery of the
disc d will vary more or less according to the relative movement of the disc e² to
the disc d' which movement is brought about by the power exerted on the pulley
or drum.
In this manner by every turn of the drum a current is transmitted to the counting
mechanism varying according to the length of the contact between the lever g and
uninsulated portion of the disc d'. The length of which contact will vary according
to the power exerted on the drum a' as herein before described. By this arrange-
ment the counting mechanism p can be fitted up in any suitable place and at any
distance from the dynamometer.
The electric counting mechanism p which is shown drawn to a larger scale in
Figures 33 to 35 consists essentially of an electromagnet M, a lever / which acts
as the armature and an adjusting screw s. The action is similar to that of an
electro magnetic bell ringing device and differs only in that the lever is pivotally
mounted on the axis of the ratchet wheel t and in that the pawl u is fitted on the
arm t. The dial plate is operated from the ratchet wheel t and the translating
of the units into tens, hundreds and thousands is effected by any suitable
mechanism.
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 dynamometer or apparatus for measuring mechanical power consisting of
two eccentrics placed in proximity to one another on a shaft one of the said
eccentrics being fixed on the said shaft and connected by an elastic medium such
for instance as a spiral spring to a pulley or drum mounted loosely on the said
shaft, the other eccentric being mounted loosely on the first named eccentric and
connected by an arm to the loose pulley in such a manner that by the force exerted
on the pulley a variable stroke is transmitted to a lever of the counting mechanism
by means of a connecting rod substantially as and for the purpose hereinbefore
described with reference to Figures 1 to 8 of the accompanying drawings.
9
2. In a dynamometer or apparatus for measuring mechanical power the com-
bination of the eccentrics d. e the arm b, spring c and pulley a with the counting
mechanism operated from the eccentric e by a rod z and lever k segments and
pinion the whole being arranged and operated substantially in the manner and
for the purpose hereinbefore described with reference to Figures 9 to 13 of the
accompanying drawings.
3. In the dynamometer or apparatus for measuring power of the kind herein-
before described the arrangement of the elastic connecting medium in the form of
a helical spring placed in a housing & formed in one with the loose pulley or
drum a whereby an arm d' of one of the eccentrics effects the expansion or
compression of the said spring and causes a variable throw of the eccentric e
connected. with the counting mechanism substantially as and for the purpose

page_text: herein before described with reference to Figs. 14 to 19 of the accompanying
drawings.
4. In the dynamometer or apparatus for measuring power of the kind herein-.
before described, the eccentric e for communicating a variable throw to the
counting mechanism the said eccentric oscillating on a pin and being moved to
alter its eccentricity by the pulley or drum a by means of the toothed segments 1 n
substantially as and for the purpose herein before described and illustrated with
reference to Figures 20 to 26 of the accompanyings.
5. In the dynamometer or apparatus for measuring power of the kind herein-
before described the employment of two concentric metal discs each having its
circumference, or part of its circumference covered with insulating material, the
insulating material on the two discs being separated from each other more or less.
according to the peripheral force exerted on the pulley a through an elastic medium
connecting one of the discs to the shaft (on which the dynamometer is mounted) so
as to present to an arm connected with a source of electric energy and to the
connecting mechanism for a longer or shorter period, an uninsulated part of the
periphery of one of the discs, so that a circuit is completed to electrically operate.
the counting mechanism substantially as and for the purpose herein before described
with reference to Figures 28 to 35 of the accompanying drawings.
Dated the 30th day of January 1894.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, Agents.