Improvements in Magneto Electric Machines.
Year: 1892

page_text: Date of Application, 9th Feb., 1892-Accepted, 12th Mar., 1892
COMPLETE SPECIFICATION.
Improvements in Magneto Electric Machines.
1, JOHN HUNT, of Number 127 Fifth Avenue, in the City of New York, in
the County and State of New York, United States of America, Manufacturer,
do hereby declare the nature of this invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:—
This invention relates to magneto electric machines employed for generating a
single impulse of electric energy and sending it over a line or circuit. Such
machines are most commonly used for blasting purposes for igniting electric fuses
or primers. For this and other analogous purposes a powerful instantaneous
current is required to be produced by the operation of a portable machine manipu-
lated by hand.
Machines of this character have been operated by a rotary crank, by a pull-over
lever, and by a push-bar to be thrust or slid downward. My improved machine is
constructed to be operated by pulling upwardly on a handle. In order to steady
the machine it is provided with projecting flanges or foot-rests on which the
operator may place his feet, so that by his weight he holds the machine down firmly
in place, while he is enabled to exert his strength to the best advantage in pulling
upwardly on the handle. By this upward pull the armature of the magneto
machine is revolved through suitable intervening mechanism, thereby highly
energizing the field-magnet and sending out a suitable current over the line.
Fig. 1 of the accompanying drawings is a front elevation, and Fig. 2 is a side
view of my improved machine illustrating its mode of operation;
Fig. 3 is a front view of the machine with the enclosing case in section ;
Fig. 4 is a vertical transverse section of the enclosing case showing the machine
in side view ;
Fig. 5 is a fragmentary front view showing the mechanism in operation;
Fig. 6 is a fragmentary section on the line 6-6 in Fig. 4 and looking toward the
front;
Fig. 7 is a diagram illustrating the electrical connections;
Fig. 8 is a rear elevation answering to Fig. 6, but showing a modified con-
struction of a circuit-breaker, and
Fig. 9 is a similar view showing the parts in a different position.
Within an enclosing box or case A is mounted the magneto electric machine
proper B and the mechanism for driving it. This magneto machine is constructed
n any usual manner with a field-magnet wound with suitable exciting coils and
having an armature a revolving in the polar gap of the field. On the shaft 6 of
his armature is fixed a pinion c with which meshes a driving gear d fixed to a
inion e.
This latter pinion is engaged by a sector C carried by a vibrating
rm D fixed on a rock-shaft E. The outer end of this arm is connected by a link f
ith a vertically sliding pull-up bar F, which passes out through the top of the
ox and carries a handle G, being guided in its vertical motion by a tubular
earing g
By pulling upon the handle G the arm D is swung from its lowest position shown
Fig. 3 to or beyond the position shown in Fig. 5, and during its movement the
ector C remains in mesh with the pinion e, and through the train d
mature at a multiplied velocity.
C
drives the
At the extreme upstroke of the handle :
e sector C passes out of mesh with the pinion e, permitting the armature to
eely revolve, and during the lowering or dropping back of the handle to its.
ormal position, the sector remains out of mesh with the pinion. To accomplish
[Price 8d.]

page_text: this result, the sector, the pitch of the teeth of which when in the normal or
engaging position is in the arc of a circle concentric to the axis of the shaft E, is
itself pivoted to the arm D eccentrically on a pivotal stud h, so that by turning on
this stud its gear teeth are brought out of mesh with the teeth of the pinion. The
shaft E is arranged sufficiently below the axis of the pinion e, so that when the
operating handle reaches the top of its movement, the centre of gravity of the
sector passes to the right of its pivotal axis so that it falls outwardly to
the position shown in dotted lines in Fig. 5. The extent of its movement rela-
tively to the arm D is limited by suitably acting reciprocal stops having the
proper amount of lost motion between them. These are most readily constructed
as a slot i in the sector engaged by a pin j on the arm D. In operation the
handle will normally be held at the top of its stroke for a moment, while the
rotation of the armature under its momentum continues until stopped by
the magnetic drag of the field poles, after which the handle will be released
and dropped back to place, and during this return movement the sector C will
fall back to its lower position. If the handle is dropped back quickly, the
sector in falling back will remain out of contact with the pinion, but if the handle
is lowered slowly, the sector will drop against the pinion and its teeth will click
over this pinion as it moves down.
.
The mechanical movement thus described is very simple and effective and takes
the place of the ratchet and pawls heretofore used for imparting motion to an
armature shaft in one direction and running free therefrom on the return stroke.
The use of this mechanism, however, is not essential as it may be variously
modified.
In order to hold the machine down and prevent its being lifted bodily by a
sudden upward pull on the operating handle, I construct the enclosing box with
foot-rests consisting preferably of lateral projections or flanges kk at the opposite
sides, upon which the operator may place his feet, so that he is enabled by his
weight to hold the box firmly down in place while he is pulling upwardly on the
handle. The reaction of his upward pull is thus exerted against these foot-rests
and consequently against the box, so that the reaction is utilized to resist the pull,
and prevent the displacement of the machine thereby.
The distinctive feature of my invention is in the application of a pull-up handle
as the means for onerating the machine in lieu of a rotary crank, an angularly
moving lever, or a push-down bar, and in connection with foot-rests for holding the
machine down by the weight of the operator thereon. The advantages of a pull-
up handle are, first, that a person can exert greater strength in an upward pull
than in a downward push or a lateral thrust; second, that the firm anchoring of
the machine during the operation is greatly facilitated, it being necessary that
such machines shall be portable; third, an upward pull has no tendency to over-
throw the machine as is inevitably the case with a lateral thrust, and as is liable
to be the case with a downward thrust in case the operator is unskilful. The
operation of my machine requires no previous experience, the operator being
merely directed to place his feet on the foot-rests and pull upwardly on the
handle, commencing slowly and pulling continually faster and harder until the end
of the stroke.
In machines of this character it is found practically necessary to short-circuit
the machine at first in order that the current generated may be utilized in exciting
the field-magnet to build up its magnetism to the requisite extent for generating
in the armature the electro-motive force necessary for overcoming subsequently
the resistance of the line. If the entire current were at first sent over the line,
the resistance of the latter would reduce the current to very small volume and the
magnetization of the field would consequently be very slight, and the field would
fail to build up sufficiently to generate the requisite electro-motive force in the
armature for forcing a strong enough current against the line resistance to insure
the proper exploding of the fuses. It is hence customary in such machines to
commence the operation of the machines on a short-circuit in order that the entire

page_text: electro-motive force generated may be utilized in driving a current of compara
tively large volume through the coils of the field-magnet, and toward the end of
the operation to break this short-circuit and thereby send the entire electro-motive
force over the line. By thus accumulating energy in the field-magnet, the current
sent over the line is rendered much more energetic than could otherwise be the case.
For accomplishing this purpose I provide the circuit-breaker shown in Fig. 6,
consisting of two arc-shaped strips of metal m n fastened against an insulating
plate P and traversed by an arm M of spring metal mounted on but insulated
from the rock-shaft E, by which this arm starting from the position shown in full
lines in Fig. 6 is caused to move angularly until it reaches the position shown in
dotted lines. These arc-shaped strips are connected in the short-circuit p p in the
manner shown in Fig. 7, so that this short-circuit is completed through the medium
of the arm M. The short-circuit continues to be thus maintained during the first
part of the stroke and as long as this arm M is sweeping over the arc-shaped
strips, but toward the end of the stroke the arm passes off these strips, the short-
circuit is broken, and the current is consequently forced over the connections o̟ o̟ to
the binding posts: H H³, and hence over the exterior line I, thereby exploding the
fuses rr. The circuit-braker thus provided is very simple in construction, is not
liable to get out of order, and has the advantage of keeping the conducting surfaces
always bright and free from oxide by reason of the rubbing of the elastic metal
arm M over the strips m n.
A modified construction of circuit-breaker is shown in Figs. 8 and 9. On the
shaft E is fixed in lieu of the spring arm M a cam or sector Q. A contact arm N
euters at its upper end between two springs s, the short-circuit p being completed
through the springs s and arm N as shown in Fig. 8. The arm N has a sp
tending to throw it away from the springs s to the position shown in Fig. 9, rit
is normally held against the contact springs by a catch t having a shoulder engaging
a pint on a contact lever. On lifting the operating handle, the cam Q is oscillated
from the position shown in Fig. 8 to that shown in Fig. 9, and toward the end of
its movement a pin u carried thereby strikes the under side of the catch and lifts
it, thereby freeing the pin t¹ from its shoulder, whereby the contact arm N is set
free and flies outward under the tension of its spring, thus breaking the short-
circuit as shown in Fig. 9. During the return or downward movement of the
operating handle, the cam Q in oscillating back to its normal position, strikes a
projection on the arm N and forces this arm back to its normal position, so that
the catch lever or pawlt which is lowered by the descent of the pin u until it rests
on the pin t', is finally dropped into its normal position with its shoulder engaging
this pin. The pin is designed solely for the purpose of preventing the catch t
being thrown too high. This construction affords a quick action or snap-switch so
called. The construction of switch first described is preferable on account of its
greater simplicity and the ease with which the conducting surfaces are kept
bright.
My invention may be greatly modified in matters of detail without departing
from its essential features. Thus the details of the cut-out are not broadly
essential, nor is it broadly essential to my invention what construction of intervening
mechanism for imparting motion from the operating bar to the armature shaft is
employed.
Having now particularly described and ascertained the nature of the said inven
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. An electric generator comprising a portable box; constructed with opposite
foot-rests upon which the operator may stand, a magneto-electric machine enclosed
in said box, a pull-up operating handle above the latter, a vertically-movable con-
nection passing from said handle through the top of the box, and mechanism
connected thereto for imparting rotation to the armature of the magneto-electrio
machine upon pulling said connection upwardly, whereby the weight of the operator

page_text: "
-standing on said foot-rests and the reaction of his upward pull are utilized for
holding the box down in place during the operating stroke, substantially in the
manner set forth.
2. An electric generator comprising a box having foot-rests constructed as lateral
projections at its base on which the operator may stand to hold down the box, a
pull-up operating handle, and a magneto-electric machine with its armature con-
nected to said handle to be revolved by the upward movement thereof, substantially
as and for the purposes set forth.
3. An electric generator comprising a box, a vertically sliding pull-up bar
movable through the top of said box, a magneto-electric machine in said box, a
pinion in connection, with the armature shaft of said machine, a sector meshing
therewith and connected to said bar, whereby during the upward movement of said
bar it drives said armature, and means for disconnecting said sector from the
armature during the downward movement of the bar, substantially in the manner
and to the effect set forth.
4. An electric generator comprising a box, a vertically sliding pull-up bar
movable through the top of said box, a magneto-electric machine in said box, a
pinion in connection with the armature shaft of said machine, a sector meshing
therewith, an arm connected to said pull-up bar and to which said sector is
eccentrically pivoted, and stops on the arm and sector adapted to hold the sector
in mesh and concentric with the axis of said arm during the upward thrust from
said bar, and to permit displacement of the sector eccentrically to bring it out of
mesh with said pinion during the downward movement of said bar, substantially as
and for the purposes specified.
5. A magneto-machine comprising a reciprocating operating bar for driving the
armature, a short-circuit for said machine, and a circuit-breaker for said short-
circuit comprising a conducting strip and a conducting arm sweeping over and
beyond said strip to break the circuit on passing beyond it, and said arm connected
to and moved by said operating bar, substantially in the manner set forth.
6. A magneto-machine comprising an operating bar, a sector connected thereto,
the armature of the magneto electric machine driven from a pinion engaged by
said sector, a short-circuit for said magneto-machine, and a circuit-breaker in said
short-circuit consisting of two conducting strips connected to the respective
terminals of said short-circuit, and a conducting arm sweeping over said strips to
form a circuit-completing bridge between them, connected mechanically to the
sector and arranged to move beyond the strips and thereby break the circuit
before the termination of the stroke of the sector, substantially as set forth.
7. A magneto-machine comprising an operating bar for driving the armature, a
short-circuit for said machine, and a circuit-breaker for said short-circuit com-
prising a terminal-contact, a conducting-arm in contact therewith, and tending to
move out of contact therewith, a catch engaging said arm and restraining it from
so moving, and a moving part deriving motion from the operating bar and adapted
near the end of the operating stroke to displace said catch and release said arm,
permitting it to move and break said circuit, substantially in the manner specified.
8. A magneto-machine comprising an operating bar for driving the armature, a
short-circuit for said machine, and a circuit-breaker for said short-circuit com-
prising a terminal-contact, a spring-pressed conducting arm in contact therewith
tending to fly out of contact therewith, a catch engaging and-restraining said arm,
and an oscillating cam deriving motion from the operating bar, adapted near the
end of the operating stroke to displace said catch and release said arm, and formed
with a cam-face adapted on the return stroke to press back said arm and cause it
to be re-engaged by said catch substantially as specified.
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Chartered Patent Agent.