IMPROVEMENTS IN ELECTRO-MAGNETIC APPARATUS FOR OBTAINING MOTIVE POWER
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by William Clark at the Office of the
Commissioners of Patents, with his Petition, on the 6th December
.1866. A communication from abroad by Eloi Poitevin, Professor of
Natural Philosophy, of 29, Boulevart St. Martin, Paris..
I, WILLIAM CLARK, of 58, Chancery Lane, in the County of Middlesex,
Engineer and Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN ELECTRO-MAGNETIC APPARATUS FOR OBTAINING
MOTIVE POWER," to be as follows:
The motor which I am about to describe, and which constitutes the object
of my present application for Letters Patent, is intended to serve as a generator
of motive power, more especially applicable to small vehicles and boats.
"Arrangement of apparatus with one electro-magnet and one armature."-
The armature is fixed on a lever, the form of which may vary at will, but the
final purpose of which is to actuate the ratchet on the wheel. A plain efficient
interrupter of the current is fastened by soldering or otherwise on the lever.
It is only after sixteen years of repeated experiments that I am enabled to
obtain a really effective force by giving suitable proportions to the various
parts, which proportions depend on the size and qualities of the electro-
magnets which are employed..
I will now describe a motor with one electro-magnet only and one armature,
operated by a small battery charged with about one and three-quarter ounces
of a solution of bichromate of potash, and an addition of one-twentieth part of
sulphuric acid. This motor is sufficient to drive a small vehicle, such as is
shown in the Drawing annexed, for nearly one hour, and a boat for above two
hours.

page_text: E, Figure 1, shows the poles of the electro-magnet placed in the present
case horizontally. A, armature, the oscillating centre of which is at O, to
this armature is connected a bent lever (merely for sake of elegance) which
passes between the two branches of the electro-magnet, and is jointed by a
crank F, f, to another P, F, the oscillating centre of which is at P on the
motor shaft. The second lever carries the ratchet intended to act on the wheel
at a point M. I at first used but one lever, in which case the latter worked
but very imperfectly, and much force was wasted. By means of the second
lever P, F, the ratchet is made to bear very slightly on the toothed wheel,
and the spring which constitutes it is thereby constantly ready to act without
sudden start in consequence of its oscillating centre coinciding with that of
the wheel on this lever, on which chiefly good results depend. Further, the
large size of the wheel, the form and dimensions of the teeth, the comparative
length of the lever L, f, to the distance O, E; all these are not arbitrary,
there are such proportions whereby excellent results are ensured, while on the
other hand there are others which will only yield more or less rapid motions
but no utilizable power. The proportions shown, which are the results of
laborious investigations, are the most favorable. The distance O,f, is to be about
four times greater than the distance O, E, and the diameter of the toothed wheel
nearly the same length as O, f. The Drawing shows the exact proportions of all
the parts. The teeth of said wheel are about three hundred in number; they
are inclined but may be made straight, the pitch should be from ths to
Tths of an inch for the small electro-magnets, and for the large ones Toths
of an inch and more. There are also other parts which are not less difficult
to construct in order to obtain beneficial results. 1st, the distribution of the
current which forces the levers forth in the direction of the arrows; and,
2ndly, the antagonistic spring which forces the same back.
The following is the best arrangement as regards the first part or the
distributor. On the armature is soldered somewhat obliquely a steel blade
'sufficiently resistant, and of 16ths to 13ths of an inch wide by ths long, having
the thickness of a watch spring; under the action of the antagonistic spring R
the small blade r abuts against the point of an insulated metallic screw V and
ending in the positive pole of the battery, it is by this contact that the current
is established, and the arrangement and force of this spring presents the
greatest difficulty in the construction of my motor, for should the proportions
given be ever so little overlooked, the motion, as aforesaid, will be obtained
but no utilizable power, and therefore my improvements are not based on the
apparatus for producing motion; but on the arrangement whereby force will be
obtained as by my motor. I shall presently describe another distributor of the

page_text: current as intended for electro-magnets of far larger size. The one on the
small vehicle and boat only weighs from 3. to 8 oz. (comprising the iron and
electric wire.) The antagonistic spring R also requires great care, and must
be from 1 to 1 of an inch long, and abuts against the lever at a point g more
or less close to the point o, according to the force of the electro-magnet; if
the point g is too remote from the point o the construction will be defective
preferably it should be too near than too remote from it. A screw B will
regulate the force of this spring, which is nearly of the same nature as the
small spring r. The main spring R is in communication with the body of the
motor, and thereby with the zinc pole of the battery. When the armature is in
contact the small blade r is not to be more remote from the end of the screw V
than a fraction of a line. In this case the current is interrupted, the anta-
gonistic spring R repels the armature, and the small blade r comes in contact
with the screw V, the current is immediately re-established, but not so as to
overcome the resistance. of the spring R. As the small blade r is sufficiently
resistant, and not only touches but roughly rubs the ends or point of the screw
the current is forcibly established, but the armature has no great resistance to
encounter until it has moved back more than 8ths of an inch; when the current
is stronger than the spring R the armature is quickly attracted, and as much in
consequence of the remaining magnetism as well by the speed acquired
arrives at the contact point notwitstanding the interruption of the current and
the resistance of the spring R. These conditions deeply examined enabled
me in giving the lever L a sufficient length to impart thereto a course of th
of an inch at least, or even 12ths or 13ths of an inch, and yet the force is con-
siderable enough to move the wheels of the vehicle or boat fixed on the shaft P.
Such is the motor which I claim to be new, the proportions of which are so
contrived as to obtain with a single small electro-magnet a single armature
and a single element of pile of. bichromate of potash a force which was never
obtained heretofore and which seems never to be surpassed.
:
I may, as herein-before hinted, by using a large electro-magnet change or
modify the arrangement of the various parts of my apparatus; these new
arrangements which I claim are the following
:-
Figure 2, the lever has its oscillating point at P on the wheel-carrying
shaft. The armature is at A at a greater distance than the radius of the
toothed wheel; the lever may be horizontal and no antagonistic spring is
required, the very weight of the armature sufficing to cause its rapid fall. The
contact is effected by means of mercury (or it may be with metallic blades),
at C at the end of the lever; an insulated metallic fork is made to dip by
its two prongs x, y, at once into two cups containing mercury and communi-

page_text: cating the one x with the positive. pole, and the other y with an end of the
electric wire of the electro-magnet. The prong y is constantly immersed in
the mercury, while the prong x is dipped only by intermission. Supposing
both x and y immersed the current then excites the electro-magnet, the
armature is quickly attracted, but almost immediately the prong x is out of
the mercury; nevertheless, in consequence of the speed acquired and the
remaining magnetism, the armature continues its motion and arrives in contact
with the electro-magnet, then the current being interrupted it falls down again
when on the spring & touching the mercury again the current is re-established;
but the the electro-magnet in consequence of its size requires more or less time
to recover the requisite force to attract the armature again in spite of its
resistance. For this reason the prong x dips into the mercury to a certain
extent, and the movement of the armature can be immediately sufficient to
enable the ratchet on the lever, which pushes the toothed wheel at M to take
one or more teeth, but the remaining magnetism of the large electro-magnets
is so persistent that the armature might remain too long in contact, and in this
manner whatever is gained in power would be lost in speed. I have therefore
invented the following arrangement :-
Figure 3, the armature is itself surrounded by a pretty thin electric wire,
not too long (one or two turns are sufficient), one end of this wire commu,
nicates with the iron itself of the armature, the other (sufficiently flexible so
as not to hinder the movement of the armature) communicates with the
positive pole of the pile, or of a small special pile, the negative pole of which
communicates on the other hand with the iron of the electro-magnet. The
wire is disposed on the armature in such a manner that it serves to magnetize
it inversely to the action produced thereon by the electro-magnet. When this
armature comes in contact, then only it is under the influence of the current
and assumes a different magnetism from that imparted thereto by the
remaining magnetism of the electro-magnet, and therefore it is repelled more
or less quickly, and thus then a large electro-magnet is as prompt as a small
one to permit the return of its armature, but not so quick as a small one to
recover the maximum magnetic force sufficient for the work; and therefore, in
consequence of the oscillations of its armature being far more considerable, I
can change the form of the lever and act more directly on the toothed' wheel..