IMPROVEMENTS IN THE CONSTRUCTION AND ARRANGEMENT OF APPARATUS AND MECHANISM FOR INDICATING THE NUMBER OF REVOLUTIONS PERFORMED BY. WHEELS AND OTHER ROTATING MACHINERY
Year: 1876

page_text: LETTERS PATENT to Thomas Dunn, of Threadneedle Street, in the City of
London, for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION AND
ARRANGEMENT OF APPARATUS AND MECHANISM FOR INDICATING THE NUMBER
OF REVOLUTIONS PERFORMED BY. WHEELS AND OTHER ROTATING MACHINERY."
Sealed the 13th April 1877, and dated the 25th October 1876.
PROVISIONAL SPECIFICATION left by the said Thomas Dunn at the Office
of the Commissioners of Patents on the 25th October 1876.
THOMAS DUNN, of Threadneedle Street, in the City of London. "IMPROVEMENTS
IN THE CONSTRUCTION AND ARRANGEMENT OF APPARATUS AND MECHANISM FOR
INDICATING THE NUMBER OF REVOLUTIONS PERFORMED BY WHEELS AND OTHER
ROTATING MACHINERY."
This Invention relates to the construction and arrangement of apparatus and
mechanism whereby the number of revolutions performed by wheels and other
rotating machinery is indicated in an accurate manner, and it thus enables persons
travelling in any vehicle mounted' on wheels or in any vessel propelled by machinery
to ascertain at any time the distance travelled, and also the rate of speed at which
the vehicle or vessel is progressing by simple reference to the indicator.
The nature of the Invention will be best understood by describing its application
to a wheel, as the application thereof to rotating shafts and other machinery will be
evident to and will be well understood by persons conversant with mechanism and
mechanical contrivances. On one side of the wheel near its centre is fixed a button
or cam-like projection, or a circular disc is eccentrically fixed thercon, by either of
which means a lever so placed as to come into contact with the button, cam, or the
projecting side of the disc is caused to make an oscillation with each revolution of
the wheel, and the necessary motion is communicated from it to the instrument by
a cord suitably arranged, or by preference a ring is mounted on screws eccentrically
arranged on the side of the wheel so as to impart to the ring within which they
revolve an oscillating motion which is communicated to the instrument by a rod
screwed into the ring. In a box of any suitable size is placed horizontally a lever,
to one arm of which is attached one end of a vertical rod, to the other extremity of
which is attached the cord from the oscillating lever or the rod connected with the
eccentric ring, whereby it imparts to the lever an oscillating motion to each turn of

page_text: the wheel. On the smaller arm of the lever is mounted a pawl or detent which is
made to gear into the teeth of a ratchet wheel by means of a spring, and for every
oscillation of the lever causes the said wheel to rotate the distance of one tooth,
the said wheel being prevented from rotating in the reverse direction by the action
of another pawl or detent suitably placed for that purpose. The said ratchet wheel
is fixed on an axle bearing a pinion which gears into the teeth on the periphery of
a wheel fixed to an axle, on which is loosely mounted a cylindrical drum with a
similar wheel attached to the other side thereof; the drum with the latter wheel
however are mounted in a sufficiently tight manner as to secure their rotating with
the axle and the other wheel, which rotation is imparted thereto by the pinion con-
nected with the ratchet wheel.
An endless band of paper, parchment, or by preference of any other material,
(such as india-rubber) or combination of materials possessing with the desired degree
of strength and pliability a certain degree of elasticity is passed over suitable
carrying rollers so arranged as to allow of the endless band being of considerable
length, and then over the above described cylindrical drum, and upon the latter
being caused to rotate, as above described, the band is made to travel with a regular
and uniform speed, the said band being graduated or marked in such a manner (as
will be well understood) that certain spaces on the surface thereof will correspond
with a given number of revolutions of the wheel, and thus the number of the latter
performed or distance travelled can at once be ascertained by looking at it through
an aperture or opening in the box.
In order to reset the band to zero when desired to commence a new reckoning,
a pinion is provided, the teeth of which take into the teeth on the periphery of the
wheel attached to the cylindrical drum, which latter are caused to rotate inde-
pendently of the rest of the mechanism, and the band to travel on the pinion being
actuated from without by means of a key, button, or other suitable contrivance
attached to one end thereof.
When the instrument is employed to indicate not the number of revolutions of
machinery but the distance travelled by a vehicle or vessel, in the event of the wheels
or propellors varying in their action from any cause, such in the case of the former
as wearing of the tyres by which the wheels would make a greater number of revo-
lutions than formerly in a given distance, and an inaccurate record being thus obtained,
the instrument can be regulated by means of the following arrangement:-The
endless band is so arranged in the instrument that the readings are taken at a point
always diametrically opposite to the point in the middle of the part in contact with
the actuating roller, and one of the rollers carrying the two extremities of the band
as divided by these two points is mounted in a carriage which is moved by a screw
pin, so that the band may be loosened or tightened by rotating the said screw pin;
and if by these means and through the elasticity of the material of the band it be
tightened or loosened till the reading of the instrument is altered back wards or
forwards by half the amount by which its reading was found to be inaccurate in
one complete revolution of the endless band it may thus by one trial be accurately
adiusted for the future.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Thomas Dunn in the Great Seal Patent Office on the 24th April 1877.
THOMAS DUNN, of Threadneedle Street, in the City of London. "IMPROVEMENTS
IN THE CONSTRUCTION AND ARRANGEMENT OF APPARATUS AND MECHANISM FOR
INDICATING THE NUMBER OF REVOLUTIONS PERFORMED BY WHEELS AND OTHER
ROTATING MACHINERY."
My Invention relates to apparatus for ascertaining the number of revolutions
performed by wheels and rotating machinery, and for indicating distances travelled
and rates of speed by reference to the indicator.

page_text: My said Invention is adapted more particularly for application to bicycles, cabs,
and other vehicles, but is also applicable to other purposes wherein movement or
work done has to be ascertained and indicated.
According to my said Invention I cause the wheel or revolving body, say for
example the wheel of a bicycle or other vehicle to impart motion to a travelling
band upon which the indications are marked. I prefer to form the said band of
vulcanized caoutchouc or of other material or combination of materials capable of
being extended in length in order that the instrument may be adjusted and the
indications be corrected.
But in order that my Invention might be more clearly understood, I have
appended hereunto a Sheet of Drawings marked with letters of reference, corre-
sponding marks indicating the same parts in the various Figures.
The said Drawings are made about double the linear dimensions of an apparatus
which I have contrived for attachment to a bicycle to indicate the distances
traversed.
l
Referring in this place to the said Drawings, Fig. 1 represents a vertical section;
and Fig. 2 a side view of the apparatus, the outer case being removed in the last
Figure; Fig. 3 is a part section on the line A in Fig. 1; and Fig. 4 is a top view of
the said apparatus when enclosed within its case. In the said Figs. a is an endless
band of vulcanized caoutchouc which is mounted upon a drum b and also upon four
carrier pulleys c and d. The length of the said band is such as that when mounted
upon and in contact with the said drum and pulleys the said band shall have so
much tension as that when the said drum is rotated the said band will be caused to
travel by virtue of its surface contact with the said drum. The pulley c is mounted
in a frame e, in or on which is formed or fixed a nut which engages with a screw f.
The said screw is mounted in two of the pillars g, g, which serve to connect the two
side plates h, h, in which the gudgeons of the axles of the drum b, the pulleys d, d,
and a pinion are fitted to revolve. By turning the said screw the band a may be
extended or relaxed according as the screw is turned in one direction or the other.
The drum b is mounted upon an axle which is fitted to revolve in bearings formed
in the side plates h, h, as described, and upon the same axle are also mounted two
spur wheels i, k, the wheel i being fixed to the said drum. The wheel is fixed to
the axle of the said drum and gears with a pinion 7, and on the axle of this pinion
is fixed a ratchet wheel m. A sector lever n is mounted upon the same axle as the
said ratchet wheel or upon a stud as preferred, and carries a pawl o which is kept
in gear with the said ratchet wheel by means of a suitable spring. To the lever n
is jointed one end of a rod p. By sliding or moving the rod upwards and down-
wards alternately a vibrating movement is imparted to the lever n, and the pawl o
is thereby caused to turn the wheel m to the extent of a tooth during each upward
movement of the said rod. A detent prevents the backward movement of the
ratchet wheel. The movements thus imparted to the ratchet wheel are transmitted
to the axle upon which the drum b is mounted, and the said drum is thereby
caused to rotate, and the band a is set in motion. In the example the rod P is
arranged to be drawn downwards, the return movement of the said rod and of the
sector lever being effected by means of a spring 8.
The apparatus is enclosed within an outer casing t, in the upper end of which is
fitted a transparent glass plate. A portion of the surface of the band a can be seen
through the said glass plate. Upon this surface the indications are printed, drawn,
stamped, or marked. In the example such indications are supposed to be miles
and parts of miles, the said band being supposed to be divided throughout its length
into ten equal divisions and into one hundred subdivisions; but these markings
may vary according to the size, use, and application of the apparatus, or as may be
considered to be desirable. In the example the band is seen through an opening in
a card or plate u, on which an index point and a vernier scale are engraved or
marked, the arrangement being intended to indicate distances to the hundredth
part of a mile; but for some uses or if not considered necessary or suitable the
vernier scale might be dispensed with. The wheel i which is fixed to the drum a as

page_text: aforesaid is added to the apparatus in order that the band a may be set to zero or
be otherwise adjusted independently of and more quickly than by the operation of
the rod p. A pinion formed on a spindle v gears with the said wheel, and the
said spindle is provided with a head w. By turning the said head the drum b can
be turned upon its axle and the band be set as required. The said drum is made
to fit upon its axle with so much tightness as that when the said axle is rotated the
said drum rotates with it, at the same time that when the head wis turned as
aforesaid the drum is permitted to slip upon its axle.
This arrangement may be varied, as for example, the drum may be of a loose fit
upon its axle and be pressed against the wheel i by means of a spring or springs.
The indications of the apparatus may also be varied by causing the pawl to move
the wheel k to a greater extent than one tooth at each movement, or by furnishing
the said apparatus with a drum larger or smaller in diameter. The apparatus may
thus be adapted to bicycles or vehicles having wheels of various diameters, or to
apparatus moving at various rates of speed, the drum in each instrument being
made of a diameter suitable to the size of the wheel with which the indicator is to
be connected. It is not however necessary to vary the diameter of the said drum
to suit small variations in the diameters of the said wheels, as the screw furnishes
additional means for adjusting the apparatus to suit a particular size of wheel. To
facilitate this adjustment I prefer to make the pitch of the said screw a divisor of
one of the divisions of the scale on the band, so that the extent to which the screw
has to be turned to obtain a required result may be estimated. The adjustment
may be made by estimation before attachment to a vehicle or machine, and by
experiment after attachment I prefer to make the drum b and the pulleys c, d, d, of
wood. The said pulleys may be cheaply made by turning from wood, and by fixing
wires therein to serve as axles.
The method of connection with the wheel of the bicycle or vehicle may be greatly
varied to suit varying circumstances.
By way of example I will describe arrangements which may be employed to
connect the said apparatus with the wheel of a bicycle.
In one arrangement I mount a lever upon a plate which is fitted to clamp to the
fork of the bicycle, and I fix a stud or projection on the hub of the wheel in such a
manner as that it will act upon the said lever at each revolution of the wheel. The
indicator may be fixed on the handle of the bicycle, so that the rider can see the
indications by simply looking downwards, or the indicator may be otherwise situated
as preferred or found to be convenient. I connect one end of a cord with the
.rod P and the other end with the said lever, so that when the said lever is acted
upon it pulls the said cord and thereby draws down the rod p.
In another arrangement a ring formed with a gap to pass over the axle is fixed
excentrically on the hub, and is furnished with a loose ring which acts as the strap
of an excentric, and is connected by means of a cord or of cords with the rod p.
Each time that the driving wheel revolves the rod p acted upon, and the ratchet
wheel is moved a tooth.
When applied to cabs or other wheeled vehicles, or to machinery to which the
indicator may be found to be applicable with advantage, arrangements for con-
nection may be devised without difficulty.
The apparatus represented by the Drawings may be greatly varied in form and
detail without departing from the nature and intent of my Invention, as for
example, for some uses other material than caoutchouc may be used for the band a,
as for example, paper, parchment, steel, brass, a chain or plates linked together or
other suitable material or combination of materials may be used; also the gearing
may be varied in proportions, and for some purposes additional gearing may be added.
If it be desirable to indicate greater distances or numbers than would be within
the range of one circuit of the band a, a wheel might be mounted so as to show
through an opening below the glass, and to make a partial rotation for each circuit
of the said band, and to count and indicate the numbers of the said circuits or other
arrangements having the same object may be made, as one advantage is that the

page_text: band furnishes a longer circuit than would be furnished by the circumference of a
circle which could be inscribed within the dimensions of the indicator represented;
the length of the said circuit may be increased by lengthening the indicator, or by
passing the band to and fro over additional carrying rollers.
Another important advantage is the adjustability resulting from the employment
of an elastic band.
Having now fully set forth and indicated the nature of my said Invention, and
the manner in which the same may be carried into effect, I would have it to be
understood that I claim,-
First. The apparatus formed, acting, and applied, substantially as and for the
purposes set forth and indicated.
Secondly. The employment of an endless travelling band, substantially as and for
the purposes set forth and indicated.
And, lastly. The employment of an elastic band which can be increased or
decreased in length, substantially as and for the purposes set forth and indicated.
In witness whereof, I, the said Thomas Dunn, have hereunto set my hand
and seal, this Twenty-third day of April, in the year of our Lord One
thousand eight hundred and seventy-seven.
O Signed and sealed by the said Thomas
Dunn, in the presence of
EDWARD K. DUTTON,
Agent to the Patentee,
Manchester.
THOMAS DUNN. (L.S.)