IMPROVED APPARATUS FOR THE MEASUREMENT AND REGULATION OF " VELOCITY
Year: 1882

page_text: LETTERS PATENT to Henry Selby Hele Shaw, Assoc. M. Inst. C.E. Lecturer
at University College, City and County of Bristol for an invention of
"IMPROVED APPARATUS FOR THE MEASUREMENT AND REGULATION OF
"
VELOCITY
PROVISIONAL SPECIFICATION left by the said Henry Selby Hele Shaw at
the Office of the Commissioners of Patents on the 16th June 1882.
HENRY SELBY HELE SHAW, Assoc. M. Inst. C.E. Lecturer at University College,
City and County of Bristol "IMPROVED APPARATUS FOR THE MEASUREMENT AND
REGULATION OF VELOCITY
"
This invention relates in the first place to the measurement of velocity by means
of the relative position of two pieces, one moving at a uniform speed and another
in contact with it, moving at a speed regulated by the machine, or body, whose
motion is to be determined. There is a definite relative position of the two pieces,
corresponding to every velocity of the above body or machine, from zero to the
limit measurable by the apparatus. As long as the latter velocity is uniform the
relative position of the pieces does not alter, but immediately that it changes, a
differential action takes place between the two moving pieces which causes their
relative position to correspond at any instant, within a very small interval of time,
with the variable velocity. The velocity is indicated at a glance, by the relative
position of the pieces, which is made visible and also recorded by suitable apparatus
to be hereafter described.
The mode of carrying out this part of the invention is as follows:-
A circular plate or disk is caused to revolve at a uniform rate by an electro
magnet, or other motor under the control of clockwork. This plate or disk is
pressed by a spring against a roller, the axis of which works in fixed bearings.
The axis of the roller is a screw, upon which the roller can freely revolve, being
threaded upon it, as an ordinary nut upon a bolt.
This axial screw is turned by an electro magnet or other suitable apparatus at a
velocity regulated by that of the machine or body in motion, either in close con-
nection with it, or at any distance by means of electric communication. It is

page_text: obvious that as long as the screw has the same angular velocity as the roller, their
relative position will remain constant. But when the angular velocity of the
screw changes by reason of the change of velocity of the machine or body in
motion controlling it, the roller will be compelled to change its position upon the
screw and therefore upon the disk (since the axis of both screw and disk work in
fixed bearings) and will continue to change its position upon the screw and there-
fore upon the disk until it arrives at a portion of it, at which the motion of it
corresponds with that of the screw, that is with that of the machine or body, whose
velocity is required to be known.
When the velocity of the machine or body is zero, the roller will be in the centre
of the disk, but if it be not desired to record velocities of less than a given value,
the centre portion of the disk may be removed or recessed below the surface of the
remaining portion, and the roller will then have no tendency to approach nearer
the centre of the disk than the edge of this recess. A suitable arrangement of
springs must be used to bring it on the disk when the velocity again increases.
The advantage of this arrangement is that several rollers can be more conveniently
used. By a suitable arrangement the position of the roller on the screw (the screw
and roller being respectively the two moving pieces above referred to) and thus the
velocity of the machine or body controlling that of the screw can be shown at
every instant on a graduated dial, and can also be permanently recorded on a surface
moved by clockwork.
Further it is evident that two or more rollers may be simultaneously in contact.
with the same uniformly moving disk, each roller having the velocity of its axial
screw regulated by a different machine or moving body, the velocity of each
machine or moving body being registered either on the original dial by a different
pointer or on separate graduated dials, and permanently recorded cither on the
original uniformly moved surface by a different style or if required on separate
surfaces also controlled by clockwork. It is obvious that the action of the instru-
ment can be made as sensitive as desired by sufficiently increasing the speed of the
moving pieces, and moreover, that the intermittent manner in which uniform
motion is usually obtained from the action of a pendulum or balance escapement is
in this invention of little or no consequence, since for ordinary velocities of the
disk the only appreciable motion of the roller along the axis of the screw depends
upon the continued difference between the uniform and variable velocities.
The second part of the invention relates to the regulation of velocity by the
improved manner in which the control of the velocities, of either the screw or
roller or of both is effected, which is as follows:-
This
The moving body whose motion is to regulate that of another imparts impulses
with more or less rapidity to one extremity of lever or frame, the other end of
which communicates with a space from which oxygen and the impurities of the
atmosphere are excluded, suitable purified gas being substituted for air.
space is separated from the outer air by mercury through which a portion of the
lever or frame passes, and in which it works without appreciable friction. The
small amount of working friction is an advantage of no small importance, since the
escapement and mechanism of any ordinary clock, is found sufficient to regulate
the velocity of any other piece. In the above isolated space, but insulated from
the mercury below, is a capsule of mercury, in which the lever or frame dips at
every impulse, and thus establishes, in a certain manner electrical communication,
with the two portions of mercury and so with two wires communicating with a
suitable motor or piece whose motion is to be regulated, thus oxidation of the
electrodes is to a great extent if not altogether prevented. Counting apparatus
may be added and either part of the invention may be used independently of the
other, in particular this mode of electric control may be separately applied to
regulate the velocity of any clock or number of clocks by a standard one. Moreover
the parts of the apparatus may be modified in detail.
Amongst the objects to which the invention may be applied are, First, the
measurement of the velocities of air and water by causing the ordinary fan, vanes,

page_text: or other moving portion of an anemometer or current meter to control the motion
of that one of the two above mentioned moving pieces corresponding to the axial
screw. It is obvious that velocities, at different places, (such as different points in
the section of a stream) can be simultaneously measured and recorded by one
instrument, in the manner above described.
Also, Secondly, the measurement of the speed of a ship through the water by
connection with the screw or rotator of the log, and further the number of revo-
lutions of the engine of the ship may be simultaneously recorded by the same
instrument, this arrangement being specially adapted for speed trials, particularly
for progressive ones, and for scientific experiments. In this case the ordinary lever
escapement of a common clock can be used advantageously, a pendulum escapement
not being suitable.
And thirdly, indication at a glance and record of the number of revolutions per
minute (or other interval of time) of one or more prime movers or machines, situated
at various parts of a works or factory

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Selby Hele Shaw in the Great Seal Patent Office on the
16th December 1882.
HENRY SELBY HELE SHAW, Assoc. M. Inst. C.E., Lecturer at the University
College, city and county of Bristol, IMPROVED APPARATUS FOR THE MEASURE-
MENT AND REGULATION OF VELOCITY
"
68
Since the filing of my provisional specification I have ascertained that the first
part therein described is not new, I, therefore, lay no claim to the said first part,
but confine myself strictly to the second part, which I believe to be entirely
original, and therefore claim, and of which the following is a description.
My Invention consists in the improved apparatus by which the regulation of
the motion of one piece by another is effected. The moving body whose motion is
to regulate that of another imparts impulses with more or less rapidity to one
extremity of a lever or frame, the other end of which communicates with a space
from which oxygen and the impurities of the atmosphere are excluded, a suitable
purified gas being substituted for air. This space is separated from the outer air
by mercury, through which a portion of the lever or frame, or a wire attached
thereto, passes, and in which it works without appreciable friction. The small
amount of working friction is an advantage of no small importance since the
escapement mechanism of any ordinary clock, is found sufficient to regulate the
velocity of any other piece. In the above isolated space, but insulated from
the mercury below is a capsule of mercury, in which the lever or frame, or the wire
attached thereto, dips at every impulse, and thus establishes, in a certain manner
electrical communication with the two portions of mercury, and so with two wires
communicating with a suitable motor or piece whose motion is to be regulated,
thus oxidation of the electrodes is to a great extent, if not altogether prevented.
This mode of electrical control may be applied to regulate the velocity of. any clock
or number of clocks by a standard one. The parts of the apparatus may be
modified in detail.
But in order that my Invention may be more clearly understood I will proceed
to describe the same by the aid of the accompanying sheet of drawings, in which
Fig 1 is a sectional elevation and Fig 2 a plan of the electrical contact maker, in
which A represents the escapement wheel of a standard clock, whose motion is to
regulate that of another body, and it imparts impulses to one extremity of the
lever or frame B, which turns on fulcrum C. From this lever or frame a wire D,
preferably of platinum passes into the space E containing the purified gas. This
space is separated from the outer air by mercury F through which the wire passes
and in which it works without appreciable friction. In the above isolated space E,
but insulated from the mercury below, is a capsule of mercury G. The wire D
terminates in the space E above the mercury F and is connected by a glass
junction H with the wire I, one end of which dips into the capsule of mercury G.
When the lever or framo B is depressed by the escapement wheel A, the lower end
of the wire I is caused to dip into the mercury below the space E, and the electric
circuit is thus completed. After each impulse the lever or frame B is raised again
to its normal position by the weights W, W, and the circuit thereby broken. The
capsule of mercury G is connected with a binding screw G₁, and the mercury F is
connected with the binding screw F¹, from which binding screws wires lead to the
moving part, the motion of which is to be controlled.
Portability is secured by having a plug K, which can be screwed down and a
gland L, by means of which the wire D can be packed by an india rubber
washer M. The lever or frame B and balance weights W, W, are made to go
within the lid Q which can be taken off the bottom and screwed on the top (as
shown by the dotted lines). This keeps in any loose mercury above the plug.

page_text: Fig 3 is a sectional end elevation, Fig 4 is a sectional front elevation, Fig 5 is
a sectional side elevation and Fig 6 is a plan view of a modification of my
improved controlling apparatus in which the use of mercury is abolished, but the
completion and breaking of the electric circuit is still effected in a closed space
filled with a suitable gas, which will not act on the body enclosing such space,
whereby oxidation of the same is prevented and electric contact secured.
A metal drum A is turned by a cord b or by any other means from the stardard
clock or other motor. The front face of this drum is a plate of glass G. The
drum is air-tight, so that it may be filled with and retain hydrogen or other gas,
which will not combine with the metallic contact maker within it, upon the passage
of an electric spark. P and N are two metallic springs, the former in contact
with the axis which carries the drum, and the latter with the drum itself. The
springs P and N communicate respectively with binding screws P¹ and N¹, fixed
to and insulated from the supports S, S. K is. a piece of metal which bangs from
the axis by a jointed lever L and a loose collar M, but with which it is always in
electrical contact. The drum A is insulated from the axis. The periphery of the
drum has a number of pieces of insulating material O inserted in it, and a groove Q
is turned in its interior, in which the metallic piece K rests. The action of the
contact maker is as follows:-When the axis is turned the weight of the metallic
piece K prevents it from being carried round, so that it rests alternately upon the
insulating material and the metal of the periphery of the drum, and thus contact
is made and broken. The metallic piece K is in communication with the binding
screw P by means of the spring P. The drum A is in communication with
binding screw N¹ by means of the spring N. By this means the contact is made
and broken in the gaseous space contained in the drum A. The wires leading
from the binding screws N¹ and P¹ communicate with the part whose motion is
to be regulated.
It will be readily understood that the details may be altered without departing
from the principle of the invention, for instance, a roller may be fitted on the end
of the jointed lever L and serve to make and break contact by resting on the
periphery of the drum A, instead of employing the metallic piece K for this
purpose; the binding screws P¹ and N' may be placed in any convenient position.
The connection between the interior of the drum A and the binding screw N¹ may
be effected by the employment of a bead of mercury placed in the groove inside
the drum.
Having now described the nature of my invention and the manner of carrying
the same into effect I wish it to be understood that what I claim is the improved
apparatus for causing an electric circuit to be alternately completed and broken in
a space from which air is excluded and a suitable gas introduced which will not act
upon the material of the body enclosing the space, whereby oxidation of the same
is prevented and perfect electric contact secured when the usual spark takes place,
the contact maker being actuated from any suitable standard motor, and the
electric current utilized to control the motion of other motors or moving parts,
substantially as herein described and shown in the accompanying sheet of
drawings.
In witness whereof, I, the said Henry Selby Hole Shaw, have hereunto set
my hand and seal this sixteenth day of December in the year of our
Lord One thousand eight hundred and eighty-two.