Year: 1886

page_text: I HENRY JULIUS SMITH of Mountain View, Passaic County, State of New
Jersey, United States of America 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 :-
My Invention relates to the class of dynamo-electric machines employed in
generating an intense current of electricity for firing fuses, igniting gas jets and
similar uses. In my present Invention I have placed the circuit in the top of the
casing and have provided a roller and a rod for guiding the rack bar, my object
being to remove the circuit breaking key from a point where it is continually
exposed to moisture and dirt to a point where it will always be kept dry and
accessible for cleaning.
Reference is to be had to the annexed drawings forming a part of this
Specification in which figure 1 is a side elevation of my improved igniting dynamo
electric machine with a part of the casing removed; figures 2 and 3 are respectively
front and rear elevations with parts of the casing removed. Similar letters of
reference indicate corresponding parts in the different figures of the drawings.
It is well known that the field magnet and armature of a small dynamo electric
machine may be quickly brought to saturation and that when the current is at its
maximum the breaking of the circuit will cause the extra current generated in the
coils to be discharged either through the air at the point of rupture of the current
or through a derived circuit connected with the terminals of the field magnet.
In my improved machine, I take advantage of this fact and also of the fact that an
accelerated motion of the armature is more effective in bringing the field magnet
and armature to magnetic and electric saturation than a uniform rotation of the
armature.
The field magnet A is formed of the pole pieces a secured to the yoke b in the
usual way the pole pieces being wound with a suitable quantity of insulated wire
in the direction necessary to cause one of the poles of the magnet to show a North
and the other a South polarity when the current passes through the winding of the
magnet. The polar extremities of the field magnet are concaved to receive the
armature B which is preferably of the Siemens "I" type, the armature being
journaled in yokes c c¹ secured to the sides of the field magnet. Upon one end of
the armature shaft C is placed a commutator d which is touched on diametrically
opposite surfaces by the commutator springs e e¹ which are secured to the yoke c

page_text: but insulated therefrom. Upon the opposite end of the armature shaft C between
the armature and the yoke c' is placed a pinion D which is provided with a series
of ratchet teeth f on its inner face which are adapted to engage similar but
oppositely arranged teeth y formed on the end of the armature, and upon the shaft
between the pinion and the yoke c is placed a spiral spring which tends to press
the pinion forward into engagement with the ratchet teeth g of the armature.
A rack bar E passes through the top of the casing F which supports the dynamo-
electric machine, and extends downward toward the bottom of the casing and is
provided with a right angled arm i which extends from the side of the bar opposite
the teeth, and is apertured to receive a guide rod G which is secured to the top
and bottom of the casing parallel with the path of the rack bar E. The rack bar E
passes between the yoke c¹ and the end of the armature and is held in engagement
with the pinion D by a roller j journaled in the yoke c' behind the rack bar.
The upper end of the rack bar which projects above the top of the casing F is
provided with a T-handle H by which it is moved and between the handle and
the top of the casing a pin is inserted in the rack bar and allowed to project a
short distance from each side thereof. To the top of the casing F is secured
a spring-key I which is forked at its free end and embraces the rack bar E below
the pin l.
A bridge extending over the spring key I is provided with a contact
screw m which normally rests in contact with the back of the key I. The core of
the armature B is wound in the usual way, and the terminals of the winding are
connected with the halves of the commutator cylinder d. The commutator
springs e e¹ which contact with the surface of the cylinder d are connected with the
winding of the field magnet A and the remaining terminals of the winding of the
field magnet are connected with screws n n¹ which serve the double purpose of
clamping the binding posts o o¹ upon the top of the casing F and securing the
plates pp to the under surface of the case top. The plate p communicates
electrically with the key I and the plate p¹ communicates electrically with the
bridge. By means of this arrangement of the circuit, the field magnet and
armature are normally short circuited. The wires of the external or derived
circuit in which the work is done, are connected with the binding posts o o¹ and
include the fuses, or igniters of the gas-jets. The handle H binding posts o o¹,
and the key I are enclosed by a cover J hinged to one side of the casing and
shutting down over them. The cover J is secured in a closed position by a lock q
and is provided with a handle by which the machine is carried.
To arrange my improved machine for use the binding posts o o¹ are connected
with the wire leading to the different fuses to be exploded and the handle H is
raised rotating the pinion D on the shaft C without turning the armature, the clutch
connection between the pinion and the armature permitting of this action. When
the handle H and rack bar E are pushed down quickly accelerated rotary motion
is imparted to the pinion D and the armature B is rotated between the poles of
the field magnet A generating a current which passes through the wires of the field
magnet through the screws n n³, plates p p¹, key I contact screw m, and yoke l
very little of the current passing through the external or derived circuit on account
of its comparatively low electro-motive force and the high resistance of the circuit.
The current thus produced increases rapidly as the rack bar E descends and charges
the field magnet and armature to saturation or approximately so, and just before the
rack bar E reaches the extreme limit of its downward travel the pink strikes
the spring-key I and breaks the electrical connection between the screw m at the
instant the maximum of current and of magnetization of the field inagnet is
reached, so that the extra current flowing from the winding of the field magnet
and armature is compelled to pass through the external circuit and thus heat the
wires of the fuses included in that circuit causing the explosion of the fuses at the
distant points.
As is well known the electro-motive force of the extra current from the machine
is very much higher than that of the current generated in the normal working
of the machine, and whereas the direct current from the dynamo could not pass

page_text: through the external circuit owing to its great resistance, the extra current readily
traverses this circuit as soon as the short circuit is broken and performs the
required work.
The ratchet connection of the pinion with the armature permits of again placing
the machine in condition for operation without revolving the armature in the
reverse direction thus avoiding the depolarization of the field magnet.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed I declare that what
I claim is;
1. In an igniting dynamo electric machine, the combination with the dynamo
provided with a clutch pinion D of a rack bar E engaging the pinion and the guide
roller j for holding the rack bar in engagement with the pinion substantially as
herein shown and described.
2. The combination with a dynamo, provided with a clutch pinion on its
armature shaft of the rack bar E having the right-angled apertured arm i and the
guide rod G received in the aperture of the arm i and arranged to guide the rack
bar, substantially as herein shown and described.
3. In an igniting dynamo, the combination with the operating rack bar E of
a spring key I placed above the dynamo and arranged in the short circuit of the
machine and in the path of the pin projecting from the rack bar and a contact
arranged above the spring key and in the short circuit of the dynamo, substantially
as herein shown and described.
4. The combination with the dynamo A and its casing, of a hinged cover J fitted
to the top of the dynamo case and arranged to cover the parts of the igniters
extending above the top of the case, substantially as herein shown and described.
5. The combination with the operating device of the rotary armature of a
dynamo-magneto-electric machine, of a bridge or key arranged in the short
circuit of said machine and in the path of said operating device and adapted to be
opened by direct impingement of said device thereupon, substantially as and for
the purpose set forth."
6. The combination with the operating rack bar of the rotary armature of a
dynamo-magneto-electric machine, of a short circuit or bridge consisting of a spring
key and a yoke with which said spring key is kept in contact by its elasticity,
said spring key being arranged in the path of the rack bar so as to be struck and
removed from the yoke by said. rack bar at or near the completion of its armature-
operating stroke substantially as described, whereby the short circuit of the
machine is broken and the extra current of electricity caused to pass wholly to
a working circuit for application to its intended purpose.
7. The combination with the rotating armature of a dynamo-magneto-electric
machine, of a loose pinion arranged upon the arbor of the armature, a rack bar
gearing with said pinion and a clutch for engaging with and disengaging from said
pinion causing the arbor and armature to revolve therewith when rotated in one
direction, but which disengages therefrom and permits said pinion to revolve in
the opposite direction independently of the arbor and armature substantially as
described whereby is secured a rotation of the armature in one direction only and
depolarization of the magnet prevented.