Improved Speed Indicator with Centrifugal Governors.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improved Speed Indicator with Centrifugal Governors.
I, JOHANNES AUMUND, of 8, Boersenstrasse, Zürich, Switzerland, Engineer, do
hereby declare the nature of this invention to be as follows:-
This invention relates to an improved speed indicator with centrifugal governors
and its object is to remedy the defects inherent in the ordinary form of such
indicators, namely the irregular movements of the indicator arm, due to the
frictional resistance and wear of the bearings.
In carrying my invention into effect I mount the pendulum governors on
grouped cog wheels which engage in fixed racks mounted on the driving shaft
and by their movement under the influence of the centrifugal force of the
governors actuate a movable rack which in turn is connected with the recording
mechanism of the indicator by means of suitable racks and grouped cone wheel
gearing.
Improved Speed Indicator with Centrifugal Governors.
I, JOHANNES AUMUND, of 21, Börsenstrasse, Zürich, 1., Switzerland, Civil
Engineer, 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 an improved speed indicator with centrifugal governors
and specially has for its purpose to provide an indicator, in which all pivot- or
shaft-bearings are avoided in the pendulum mechanism and only a rolling
movement is employed, thus enabling the indicator to move in perfect accordance
with the true speed of the machine controlled.
In the existing forms of speed indicators with centrifugal governors, the con-
version of the pendulum motion of the governors into a reciprocating movement is
effected by means of fixed pivots, fitted with pins, or by fixed bearings.
It is thus evident, that being under the influence of the centrifugal force of the
governor pendulum, the pins or pivots will offer some frictional resistance to the
free movement of the governors, and thereby prevent the latter from promptly
changing their position, when a slight variation of speed occurs.
As the variation in speed increases, a sudden "give" ensues whereby the

page_text: governors are forced beyond their true position; the consequence being that the
indicator receives a jerky impulse, which it has been attempted to obviate by
artificial choking or braking.
When moreover, the revolving reciprocating transmission piece is guided in
fixed bearings, another inconvenience arises from the circumstance that rings are
worn in each shaft or arbor by protracted running in pillows or bearings, which
rings will run in corresponding rings of the bearings and thus form another
obstacle to the free movement of the transmission piece, and accurate working
of the indicator becomes impossible from the causes above described.
Furthermore the precision of this working depends greatly on the regular
lubricating of the said pillows or bearings, and also on the lubricating material
employed.
All these disadvantages are overcome by this invention, all pivot- or shaft-bearings
being dispensed with in the pendulum mechanism, and only a rolling movement
being employed which offers the least resistance to the accurate adjustment of the
governors and thereby enables the indicator to move in a perfectly smooth manner
and in accordance with the true speed of the machine controlled. Moreover it
becomes superfluous to attend to or lubricate the interior organs; and the wear
and tear, inevitable in pivots and bearings, is completely prevented.
In the accompanying drawings.
Fig. 1 represents partly a sectional view, partly a side elevation of the speed
indicator with centrifugal governors. The Figures 2 and 3 are transverse
sections.
In these drawings, the improved indicator is shown as a specimen of this inven-
tion, a (Fig. 1) being the driving shaft, which carries a disc a¹ in the interior of
the casing. On this disc, four racks bb are so arranged that their teeth face each
other. Four cog wheels cc engage with the racks and between these, also engaging
with toothed wheels, is a four-sided rack d which is toothed on all four sides.
Some or all of the cog-wheels c c carry the pendulums ee which encompass the
racks by means of forked arms.
The centrifugal force produced by the rotation of the shaft a, acts on the
governing pendulums and thereby tends to turn the wheels c c which in turn
displace the rack d.
At their extremities, the rack bb are connected by a cruciform plate f which
carries a sleeve g. This latter has an interior thread at g' and the piece is screwed
therein. The one end of the tension spring k butts against the piece and its
other end rests against a shoulder of the rack d, and thus causes this rack and its
appendages to return towards their original position when the centrifugal
force decreases in consequence of a reduction of speed.
The sleeve g is provided at 2 with annular interior grooves, so that it represents
a rack when viewed in cross section. Into the said sleeve are set four other cog
wheels ii which engage with the rack work of the sleeve and which guide between
them the grooved cylindrical extension of d, this extension also representing a rack
in its cross-section.
The cog wheels have a uniform number of teeth in each group and the
extremities of their axes are formed into cone-wheels which gear into one another
and thus ensure uniformity of motion and action in guiding the cylindrical rack.
Figure 2 shows this arrangement for the wheel-group cc, and Figure 3 for the
wheel-group ii, the latter being shown on an enlarged scale.
In Figure 1 one half of the lower part is shown at rest, while the other half is
represented with the pendulum stroke near its farthest limit. While the pendulum
is traversing the way from el to e, the wheel c rolls from c¹ on the rack b, and
thereby displaces the rack d, which it engages. As all wheels of this group have
a uniform number of teeth and are engaged with the rack d, all the wheels advance
or return through an equal length of travel, as the pendulum moves. They
therefore always remain in the same relative position to each other, and move

page_text: together by reason of the mutual engagement of their cone-wheel appendages.
The same is true of the wheels of group ii, which also move with the movement
of the rack d, their traverse being just half that of d, and they are always kept in
the same relative position to each other and actuate each other by their cone-
gearing.
The movement of the rack d, caused by the pendulum stroke is then transmitted
in a suitable manner to the indicator mechanism. The indicator is represented
in Figure 1 by the lever 7.
As shown in this figure, the effective length of the pendulum arm becomes
shortened during the stroke of the pendulum; this arm pivots in the pitch-line of
the rack b and its effective length, when at rest, is equal to a e¹ whilst near the
extreme reach it is equal to x e.
Consequently, with lesser velocities a comparatively greater energy is obtained
than with greater velocities and the tension of the spring is less influenced by
equal variations of velocity when its limit of elasticity is approached. Hence
the spring is protected and the object of enabling the diagram to be used within
the widest possible limits is attained.
Having now particularly described and ascertained the nature of my said inveu-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
1. A. speed indicator with centrifugal governors, substantially as set forth
and shown in the drawings.
2. In the speed indicator with centrifugal governors of the first claim, the
arrangement of groups of toothed wheels, which being engaged with racks rotating
with the driving shaft are guided by cone-gearing, substantially as set forth and
shown in the drawings.
3. In the speed indicator with centrifugal governors of the first claim, the
arrangement of the pendulums in such a manner that the effective length of their
arms becomes shortened during the stroke of the pendulum and pivots in the
pitch-line of the corresponding rack, substantially as set forth and shown in the
drawings.
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