Year: 1887

page_text: Date of Application, 5th Sept., 1887.
Specification Accepted, 7th Oct., 1887
I HERMANN HARTIG of Kändler near Limbach in the Kingdom of Saxony and
Empire of Germany, Sewing Machine 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 :-
In electro motors having rotating armatures, as hitherto constructed, the attraction
of the armature by the electro magnets is in a lateral direction, or at right angles to
the axis of the magnet.
If however the experiments that I have made can be relied on, the attractive force
is less effective than when the armature is attracted in the direction of the axis of the
electro magnet, as in the latter case the whole pole surface acts on the armature.
To provide means for applying this principle, is the main object of the present
invention.
In the accompanying drawing,-
Fig. 1 shews my improved electro motor in elevation, a portion being in
section, and
Fig. 2 is a half plan of the same.
a a are the electro magnets, fixed to an annular plate c supported in a suitable
framing. Within this annular plate c, and concentric therewith, is mounted a
wheel d, which is keyed to a vertical shaft d' supported in a footstep in the bed plate
of the machine, and in a bearing in the upper part of the framing.
This wheel d carries the armatures bbb, it being provided with bracket arms mm
for that purpose.-Each armature is carried by a sliding plate g, to which it is
connected by hinge pins that leave it free to rock thereon.-The plates g are free to
slide in vertical guides formed in the ends of the bracket arms m, and a tendency
upwards is given to them by means of coiled springs g', which connect the plates
severally with their respective bracket arms.
The form of the armature b (see Fig. 1) approximates in shape to that of an
inverted T, and when attracted by a magnet, its stem will press against the sliding
plate 9,
and it will be held rigidly to that plate while moving round with the wheel a
by which it is supported.

page_text: When the armature comes within a suitable distance in front of the magnetic poles,
the electric circuit of the magnet will be closed by a suitable device, and the armature
will be attracted, but before touching the poles of the magnet, the circuit will again
be broken. The armature, as it advances to the magnet, must turn out of the way,
and it is for this purpose that it is mounted on a sliding plate, and made free to swing
on its hinge joint e.
The sliding plate 9 carries, at its upper end, a roller h, which is intended to travel
over a series of fixed cam surfaces corresponding in number to the electro magnets
employed, the object of such cam surfaces being to present the armatures to the poles
of the electro magnets against the resisting tension of the springs g', for the purpose
of lowering the armatures 6 at the proper time.
These cam surfaces (shewn at E, Fig. 1) are carried by bracket arms i secured to
the plate c and as the rollers travel over them, the armatures will be pressed down
before they come within the attractive force of the electro-magnets.
As the armature approaches the magnet, the roller of its sliding plate will leave the
cam surface, and the tension spring being left free to act, will raise the armature clear
of the magnet. This action is repeated, as the wheel d rotates, every time the roller h
passes over one of the cam surfaces k.
The number of the field magnets and armatures may vary, but will always be
unequal; thus, the numbers of the magnets or armatures divided the one by the
other will leave a remainder, as for instance, 7 magnets, and 6, 8, 13 or 22 armatures.
By this means the armatures come successively into the reach of the attractive force
of the magnets. In lieu of lifting the armatures above the magnets, the magnets may
move clear of the armatures, as shown in Fig. 3.-The magnet is fixed on an army,
which is maintained by a spring in its perpendicular position; and is pivotted to the
plate of the frame. In this case the only movement of the armature is around the
axis of the wheel w. As soon as the armature has been attracted, a projecting
piece w (see Fig. 3) strikes against the arm y, and presses it, together with the
magnet, sideways (as shown in dotted lines), thus leaving the armature free
to pass.
2
The pressing down of the armature bin Fig. 1 by the cam k requires a certain way
to be made by the rotating wheel, and for this reason the magnets a (Fig. 2) must
not be arranged too closely to each other.-But in order to utilize the space between
these magnets, I interpose a series of electromagnets A A, which I arrange outside of
the plate C on special supports, so that the armatures 6 cannot come in contact with
these magnets A A.
The armature B of the magnet A forms a lever of the second order; it is attracted,
like the armatures b, in the direction of the axis of its magnet, and does not slide over
the magnet, but swings on its fulcrum C.-The armature, in moving towards the
magnet, may be coupled by any suitable device with the wheel d, to assist in driving
the same. I employ, for this purpose, a device somewhat like that known as the
silent feed in wheel feed sewing machines; thus, I provide a finger D (see Figs. 1
and 2) connected with the armature by means of two hinges, and so shaped as to grip
an annular projection I formed on the wheel d. A weak spring presses the finger
towards the left. As soon as the armature is attracted, the finger D turns a little,
and catches with its notch edges so as to move the wheel with certainty. The
gripping action takes place the more energetically, the more powerfully the armature
is attracted. In lieu of rotating the wheel when the armature is attracted, it may be
put in motion when the armature moves backwards; the detaching spring, in this
case, acting in place of the moving force of the electro-magnets.
In order to maintain the closed circuit for attracting the armatures B, and to break
the circuit, I have constructed for the magnets A the following contact device.
To the small shaft E (see Fig. 6) are secured the ratchet wheel F and the contact
wheel commutator G.-The latter has about 12 incisions, which are filled with an
insulating material. A spring H slides on the surface of this wheel G, and is
therefore alternately in metallic contact, and in contact with the insulating material.-
Into the ratchet wheel F, the teeth of which correspond in number with the insulators

page_text: of the contact wheel (that is to say, about 12 teeth), catch two pawls of the
armature B.-The attraction of the armature and the back movement of the same,
cause the ratchet wheel to advance each time half a tooth, so that always during the
attraction of the armature, the metal of the contact wheel rests in contact with the
spring, while at the back movement of the armature the spring rests on the insulating
material. A second spring I is always in connection with the axis E. The current
flows from the battery N through the spring I, contact wheel G, spring H, binding
post K, through the electromagnet A, and back to the battery.
The last mentioned electro magnets A, arranged in a circle, may also be disposed
in another way; the magnet may be placed, for instance, radially to the wheel, as
shown in Fig. 5, where the armature forms a bent lever, or the magnet may be
arranged perpendicularly, as R in Fig. 4, where the armature is also a bent lever, or
the magnet may lie in a vertical plane, as L in Fig. 4, the armature being here a
straight lever, but in all cases the attraction of the armature is in the direction of the
axis of the magnet.
Having now particularly described and ascertained the nature of my said Invention
and in what manner the same is to be performed, I declare that what I claim is :--
1st. The construction of electro motor as described with reference to Figs. 1 and 2
of the Drawing.
2nd. The means described, or any mere modification thereof, for presenting
armatures, carried by a rotating shaft, to a series of electro magnets in the direction
of the axes of those magnets.
3rd. The means described for imparting motion to the vibrating armatures B, and
transmitting it therefrom to the central shaft of the electro motor, for the purpose
above set forth.
Dated this 5th day at Santambor 1987