SPEED INDICATOR WITH ALARM ATTACH- MENT
Year: 1885

page_text: JOHN PEARCE 23 Park Road Glasgow Scotland Telegraph Engineer do hereby
declare the nature of said invention for SPEED INDICATOR WITH ALARM ATTACH-
MENT to be as follows:-
On a spindle there are placed two balls which rise by centrifugal force as the
spindle is revolved and as the balls rise they draw an arm forward which arm is
connected by a rack and pinion to the pointer which register the number of
revolutions, in addition to the foresaid arm there is drawn forward a cone, which
cone revolves with the spindle and as the speed increases is drawn more forward
till the high part of the cone comes in contact with a roller which roller is connected
to a revolving hammer and as soon as contact is made between the cone and roller
the hammer strikes a gong and so sounds the alarm or in place of the revolving
hammer I place a small Magneto Machine in connection with the foresaid roller so
as to ring a bell placed at a distance from the Speed Indicator.
The distance between the cone and the roller can be adjusted to ring the alarm
at any speed.

page_text: {
JOHN PEARCE 23 Park Road Glasgow Scotland Telegraph Engineer do hereby
declare the nature of my invention for SPEED INDICATOR WITH ALARM ATTACH-
MENT and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :—
And in order that my invention may be fully understood I shall now proceed
more particularly to discribe the same and for that purpose shall refer to the
several Figures on the explanatory sheet of drawings herewith annexed the same
letters of reference indicating corresponding parts; in all the corresponding Figures.
Figures 1 showes a sectional elevation of a complete Indicator, Figure 2 showes a
plan of same, On the spindle A there are placed two balls or discs. B. B. which
are kept on the side of the spindle A by a coiled spring, but when the spindle A
revolves, the centrifugal force overcomes the spring, and so allows the balls or
discs B. B. to rise or fly out.
The balls or discs B. B, acting on the principle of the ordinary governing balls
of a steam engine, but in an horizontal position, therefore the necessity of a spring
to bring them to rest, as instead of overcoming the weight of the balls, I have to
overcome the tension of the spring.
To prevent the balls or discs B. B. overcoming the spring too quickly, I fix a
strap K to the centre of the balls or discs B. B. and cross the straps K. K. so that
when the balls or discs rise they will be drawn towards the centre, and so take the
leverage off the coiled spring.
· The necessity of the straps K. K. is that if the balls or discs were fixed on the
end of the arms they would have such leverage that the spring would be overcome
to quickly for showing the proper speed, but by allowing them to be drawn in
towards the centre it shortings the leverage and so requires more speed to overcome
the spring.
As the balls or discs B. B. rise or fly out, they draw an arm; &, forward, which
arm is connected by the rack D to a pinion wheel on the pointer E, and so
according to the speed of the spindle A so the pointer E will indicate the number
of revolutions on the dial.
In addition to the foresaid the arm G draws forward the bevel wheel or cone C
which revolves with the spindle A till the speed is so high that the bevel wheel or
cone C is drawn so far forward that it comes in contact with the bevel wheel or
cone H (as shown in Fig. 3) which is connected to the swing hammers I. I. as soon
as contact is made between the bevel wheel or cone C. and the bevel wheel or
cone H, the swing hammers revolve and strike the gong J. and so sounds the
alarm.
In Figure 3 I have made the movement more plain by showing one only of the
balls or discs B on spindle A, the dotted lines show the position when the spindle A
is revolved, and just as the bevel wheel or cone C comes in contact with the bevel
wheel or cone H.
The bevel wheel or cone H can be moved along its own spindle so as to come in
contact with the bevel wheel or cone C at any speed the alarm is wanted to sound.

page_text: When the alarm is wanted at a distance from the Indicator I replace the swing
hammers I. I, by a small Magneto Machine.
Having now described and particularly ascertained the nature of my inven-
tion, and the manner in which the same is or may be carried into effect, I would
observe in conclusion, that what I consider to be novel and original and therefore
claim as the Invention secured to me by the hereinbefore in part recited Letter
Patent is
First the fixing of the cross straps K. K. on the balls or discs so as to draw them
towards the centre, and so take the leverage off the spring as shown and described
in reference to Figure 1 of my drawing.
2nd The arrangement and construction of Speed Indicator with Alarm attach-
ment substantially as shown and described in referance to Figures 1. 2. 3. of my
drawings.