Improvements in Speed Indicators
Year: 1894

page_text: PROVISIONAL SPECIFICATION.
Improvements in Speed Indicators
We, WILLIAM MILNER, of 40 Mercers Road, Upper Holloway, Supervisor
of Mechanics and WILLIAM WILSON of 22 Chalk Farm Road, Telegraph
Instrument Maker, both in the County of Middlesex, do hereby declare the
nature of our invention to be as follows:-
The invention has for its object improvements in speed indicators and relates to
a novel arrangement and combination of parts whereby the speed is indicated by a
hand or pointer travelling round a scale the position of which hand varies in
accordance with the variation of speed of the machine or shaft whose speed is
desired to be ascertained.
For this purpose we connect a fan blower by strap and pulleys or by other
connections with the shaft or machine whose speed it is desired to ascertain and
we provide means whereby the fan can be caused to rotate in the required direction
whichever direction the machine or shaft may be rotating.
We direct the outlet orifice of this fan blower against a disc or plate which is
capable of moving freely within a cylinder or boxing; this plate or disc has
connected thereto one or more guide rods working in suitable guides and it has also
connected therewith a toothed rack which moves to and fro therewith.
This toothed rack gears into a toothed pinion on the axis of the hand or pointer
to give motion to the latter in one direction whilst a spiral or other spring acts to
move the hand or pointer in the contrary direction. As a modification the disc or
plate may be at the upper end of a lever mounted on an axis of motion having
fixed thereto a counterbalanced toothed segment acting upon a pinion on the axis
of the hand or pointer.
Also the air from the fan blower may be caused to impinge against the blades
of a wheel or paddle the axis of which is directly or indirectly connected with the
axis of the indicating hand or pointer, a suitable counteracting or balance spring
being used in each case
Dated Navamhan 20th 1904
We, WILLIAM MILNER, of 40 Mercers Road, Upper Holloway, Supervisor
of Mechanics and WILLIAM WILSON of 22 Chalk Farm Road, Telegraph
Instrument Maker, both in the County of Middlesex. do hereby declare the
nature of our invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
The invention has for its object improvements in speed indicators and relates to

page_text: a novel arrangement and combination of parts whereby the speed is indicated by a
hand or pointer travelling round a scale the position of which hand varies in
accordance with the variation of speed of the machine or shaft whose speed is
desired to be ascertained.
For this purpose we connect a fan blower by strap and pulleys or by other
connections with the shaft or machine whose speed it is desired to ascertain and we
provide means whereby the fan can be caused to rotate in the required direction
whichever direction the machine or shaft may be rotating.
We direct the outlet orifice of this fan blower against a disc or plate which is
capable of moving freely within a cylinder or boxing; this plate or disc has
connected thereto one or more guide rods working in suitable guides and it has
'also connected therewith a toothed rack which moves to and fro therewith.
This toothed rack gears into a toothed pinion on the axis of the hand or pointer
to give motion to the latter in one direction whilst a spiral or other spring acts to
move the hand or pointer in the contrary direction.
As a modification the disc or plate may be at the upper end of a lever mounted
on an axis of motion having fixed thereto a counterbalanced toothed segment acting
upon a pinion on the axis of the hand or pointer.
Also the air from the fan blower may be caused to impinge against the blades of
a wheel or paddle the axis of which is directly or indirectly connected with the
axis of the indicating hand or pointer, a suitable counteracting or balance spring
being used in each case.
Our invention is illustrated in the accompanying drawings in which
Fig. 1 is a vertical section on the line 1. 1 of Fig 2 and Fig. 2 is a horizontal
section on the line 22 of Fig 1 of a speed indicator constructed according to
our invention.
Figures 3 and 4 are elevations drawn at right angles to each other and Fig. 5 is
a plan of the ratchet gearing employed to operate the gearing driving the fan
shaft.
Fig. 6 is an elevation of the train of gearing operated by the ratchet gear.
Figures 7 and 8 are respectively a sectional elevation and sectional plan showing
a slight modification Fig. 9 is a sectional elevation showing a second slight
modification, Figures 10 and 11 are respectively a sectional elevation and sectional
plan showing a third slight modification and Figures 12 and 13 are respectively a
sectional plan and an elevation showing a fourth slight modification.
In all the figures like parts are indicated by similar letters of reference.
We will first describe the instrument as represented at Figures 1 to 6.
The
shaft or other rotating body whose speed is to be ascertained is connected by a
band or otherwise with the spindle a: we prefer to accomplish this by means of a
band passing around a pulley fixed on the shaft a. The spindle a may be
connected rigidly to the fan b which rotates within the fan box 6 or as we prefer
and as shown in the drawings the spindle a may be connected with the fan b by
means of gearing in such manner that whichever way the spindle a is rotated the
fan shall always rotate in the same direction thereby enabling the spindle a to be
connected with or driven by any rotating body irrespective of the direction of
rotation of such body, or connected with a body whose rotation may be reversed as
in marine engines or the like This intermediate gearing communicating motion
from the shaft to the fan is preferably constructed as follows. On the spindle
are rigidly fixed two cams c. c, a two ended arm or lever d carrying pawls d¹² (one
at each end) is mounted looselv on the shaft a between the cams c. c¹ and these
pawls engage respectively with ratchet wheels e. el mounted loosely on the spindle
but fixed rigidly to toothed wheels f. f. The teeth of the ratchet wheels e c
point in opposite directions; the ratchet wheel e¹ not being shown in Fig. 3. Two
springs fixed to the arm or lever act to press the pawls towards their ratchet
wheels. The toothed wheel † gears with an idle or carrying wheel
which gears
with a toothed pinion and the toothed wheel f¹ gears with the pinion h; the
pinions are fixed on the shaft and on such shaft is also fixed a toothed
"

page_text: wheel which gears with a pinion fixed on the boss of the fan b. which latter
turns freely on the spindle a. If the spindle a be turned in one direction the cam c
or c will by pressing against a pin d, lift one of the pawls d¹ or d² out of gear with
its wheel e or e¹ and allow the other pawl to engage with its ratchet wheel; as
illustrated at Fig. 3, where the cam by acting on the pin d³, holds the lower
pawl out of gear with the ratchet wheel e and allows the upper pawl to
engage with the ratchet wheel e If the rotation of the spindle a be reversed, the
cam c will lift the upper pawl out of gear with its ratchet wheel e by acting on
the pin of such pawl, and the lower pawl will engage with the ratchet wheel el
as the cam moves away from the pin d of such lower pawl. Thus the fan will
be rotated always in the same direction whichever way the spindle a be turned as
by means of the idle wheel the toothed wheels f. f must always move in
opposite directions whilst the spindle carrying the wheels he will alway.
ΠΟΥΣ in the same direction and consequently drive the fan always in the same
direction.
By the rotation of the fan b a stream of air is forced through the tube 2, which is
connected by an opening with the fan box 61, and led into the annular box j. A
balanced blade k of the same shape as the section of the annular box ; but slightly
smaller, has its spindle mounted on pivots so that said blade can move freely
within the annular box j and a balance spring 7, fastened at one end to the spindle ¹
and at the other end to a post m, holds the blade k against a stop n when the fan
is at rest. When the fan b is moving the stream of air caused thereby presses
against the blade and causes it to turn in opposition to the balance spring 7; the
greater the number of revolutions per minute of the fan the farther will the blade k
be moved around the annular box 1. A pointer fixed on the end of the spindle At
moves in front of the dial provided with suitable divisions and figures and
indicates by its position the speed of the rotating body.
In the modification shown at Figures 7 and 8 in lieu of employing a balanced
blade moved by the current of air within an annular box, as described in respect
to the arrangement shown at Figures 1 to 6 we employ a disc * which is caused
to move longitudinally within a cylindrical chamber or box j This disc * is
fixed to a rod 3 passing through a hole in the bottom of the cylinder and through
another hole in a bracket by which it is correctly guided
;
To a spindle is attached a balance spring 7, a pulley and a hand or
pointer o. A flexible band q is wound around the pulley
is fixed to the said pulley and the other end to the rod ³.
pressure of the current of air set up by the fan, the disc
forward and by means of the flexible band g the spindle
to the action of the spring 7 thereon thereby carrying the
the dial p
one end of this band
In proportion to the
** and rod k³ are driven
is turned in opposition
pointer round in front of
In lieu of employing a band 7 and puller 5 as above described to give motion
to the spindle of the hand or pointer o. the rod 23 may be provided with rack teeth
gearing with a pinion on the spindle of the hand or pointer o
In the modification shown at Fig. 9 a disc or plate k is mounted at the upper
end of a lever fixed on a spindle, this spindle has fixed thereto a counter-
balanced toothed segment acting upon a pinion on the axis o' of the hand
or pointer o. The axis is acted upon by a balance spring 1 119 in the
arrangement above described and the disc or plate k is used without being enclosed
in a chamber.
In the modification shown at Figures 10 and 11 we employ a wheel ** having
a number of projecting blades which enter openings in opposite parts of the
channel or box **. The balance spring 7 and hand or pointer o are attached
to the spindle of the wheel A**. The stream of air set up by the fan is led
by the tube into the channel or box ;** and there impinges on the blades of
the wheel ** at opposite sides of the latter thereby turning the said wheel in
opposition to the action of the balance spring thereon. As the pressure of the

page_text: current of air increases the wheel is turned through a proportionately greater
angle and carries the pointer o over the divisions of the dial p.
In the modification shown at Figures 12 and 13 in lieu of the balanced blade k
or disc or many bladed wheel ** herein before described we employ a disc k***
having a series of holes therein in a circle near its periphery and a number of
short tubes fixed in said holes. The tubes are inclined to the plane of
the disc at a convenient angle. The plate 11 forming the front of the chamber
or box ***, into which the current of air, from the fan is led, is pierced with a
series of holes in a circle corresponding with the holes and tubes in the plate j.
The holes are inclined to the surface of the plate ¹ in a direction opposite to
that of the inclination of the tubes 16. A balance spring is fixed to the spindle k¹
of the dise ****. A current of an is driven by the fan b into the chamber j***
which by issuing through the holes strikes the tubes and thus causes the
dise k*** to rotate through a certain angle depending upon the pressure of the air
in the chamber or box 7***, or in other words upon the number of revolutions per
minute of the fan. A pointer o on the end of the spindle ¹ moves in front of the
dial and indicates the speed. Instead of employing tubes small flat plates
could be used.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what
we claim 18:-
1. The improvements in speed indicators substantially as
described..
herein shown and
2. In speed indicators, the combination of a fan or blower driven by the shaft
or body whose speed is to be ascertained, gearing for ensuring the fan or blower to
be driven always in the same direction whichever direction the prime shaft may be
moved, a blade, disc or wheel moved by the current of air set up by the fan, an
indicating hand or pointer and a dial and means for communicating motion from
said blade, disc or wheel to said indicating hand or pointer substantially as herein
shown and described.
HARRIS & MILLS.
23 Southampton Buildings, London, W C., Agents.