An Improvement in Electric Motors for Electric Clocks and for other purposes.
Year: 1891

page_text: Date of Application, 28th Feb., 1891-Accepted, 18th Apr.,
1891
COMPLETE SPECIFICATION.
An Improvement in Electric Motors for Electric Clocks and for
other purposes.
LEON POPE, Electrician, 10, Stonefield Terrace, Barnsbury, London, N. I 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 an improvement in electric motors for clocks, the object
being to produce an electrically actuated motor for operating the clock movement,
that will be simple in construction, efficient in operation, difficult to throw out of
adjustment, and which will require attention only at long intervals when the battery
needs renewal.
With these objects in view the invention comprises an adjustable magnet, a
circuit closer or commutator of novel construction, a novel pendulum, and other
details which will hereinafter be fully described in this Specification, and then
definitely indicated in the appended claims.
In the accompanying drawings which illustrate the invention,
Fig. 1 is a face view or front elevation of a motor embodying my invention, the
train of gearing which actuates the hands being removed and the circuit connections
with a battery indicated for clearness of illustration, and the pendulum rod shown
broken away to bring the device within the compass of the drawing;
Fig. 2 is a side elevation of the device shown in Fig. 1, the lower portion of the
pendulum being removed;
Fig. 3 is a detail view of the circuit closer or commutator.
At the upper portion of a suitable supporting frame 1. is a clamp 2 between the
jaws of which an elastic metallic tongue of steel or other resilient material 3 is held.
This tongue or strip should be of a length to give the proper resistance to the
pendulum so that the latter will not be too violently affected by the controlling
motor magnet 4. I have found that a pendulum suspended on knife edges or
suspended by a thin band of little tension is too strongly affected by the motor
magnet which gives a strong thrust to the bob, but when a spring of considerable
tension is used the mechanical resistance offered against bending prevents the bob
from swinging far from the magnet. A very light pull exerted by the magnet is
sufficient to regulate the movement of the pendulum and that is difficult to regulate
when the pendulum is free of resistance, but readily controlled by a slight
adjustment of the magnet when a spring of considerable tension used. Fixed to the
lower end of the elastic strip is a rigid bar 5 upon which the weight or bob 6 is
supported, the latter being capable of a vertical adjustment by means of a nut 7
co-operating with a screw fixed to or forming part of the rod 5. The rod 5 is rigid
and prevents vibrations of the spring strip which occur if said strip is made the full
length of the pendulum, said vibrations being independent of the pendulum motion
and liable to interfere with perfect isochronism if the strip be too long. At the
extreme lower end of the pendulum is secured an armature 8 of iron. The magnet 4
is mounted upon a support 9 pivoted to the side of the clock case and can be
adjusted vertically by means of a set screw 10 in the outer end of the support. The
magnet is secured to the support which lies in the plane of vibration of the pendulum
near the outer end of the arc of vibration. The circuit breaker slide 11 is provided
with two extensions or journals 12, 13 sufficiently long to permit the circuit-breaker
to be shifted laterally and enable a conducting strip 14 to be shifted into and out of
contact with a brush 15 mounted upon an insulating block 16. The insulating
block 16 is secured to the frame 1 so as to be capable of a lateral adjustment by means
of the adjusting screw 17, the slots and set screws shown in the illustration

page_text: permitting such lateral adjustment. An adjusting screw 18 mounted on the
insulating block permits the pressure of the brush 15 to be varied so as to insure a
good electric contact.. The projections. 12, 13 of the circuit-breaker slide are
journaled in supports 19, 20 secured to the frame.. Pins, 21, 22 project from the
front of the slide 11 and lie at the sides of the elastic strip 3. The circuit making
strip 14 is connected by means of a wire 23 with the frame 1 and the circuit
including a battery and the motor magnet has its terminals connected to the
brush 15 and the frame, as shown in the drawing. At the sides of the strip 14 are
two metallic strips, as shown in Figs. 1 and 3, mounted on the insulating block or
slide and disconnected from the circuit, their only function being to form a rubbing
surface for the brush when the latter is out of contact with the strip 14, and prevent
the wear which would occur if the brush rubbed over the soft insulating material.
The pins 21, 22 are so set or the slide 11 so adjusted in its bearings that the right
hand pin will be engaged by the strip 3 when the armature 8, at the lower end of
the pendulum, is approaching the core of the magnet 4, so that the slide will be
shifted to the right by the swinging pendulum, and the block 14 brought into
connection with the spring 15, thus closing the circuit and energizing the magnet
and giving an accelerating impulse to the pendulum. The strip 14 is of such a width
that it will have passed the platinum contact on the engaging edge of the brush 15
when the armature 8 lies over the core of the magnet 4, otherwise the magnet would
exert a retarding influence as the pendulum swings to its extreme amplitude, which
would reduce the acceleration imparted to it as it approached the magnet. The
pin 21 on the left side of the elastic strip 3 is engaged by the strip as the pendulum
swings to the left, but is secured in such a position as not to be engaged until the
pendulum approaches the left side of its arc of vibration. It will thus be seen that
every time the pendulum swings to the right it receives an accelerating impulse
which will keep it in continual vibration over a uniform are. The battery used
should be of a type which will require little attention, the ordinary gravity battery
permitting the clock to run for months without requiring any attention. As the
pendulum swings to and fro it acts upon the hand operating train of the clock in a
manner well understood, the yoke or clutch 24 co-operating with the strip 3 and
connected with a crank shaft which operates suitable pawls, not shown in the
drawing. The train of gearing is secured to posts 25 on the frame 1.
itself is supported by screws to the clock case.
The frame
I desire to have it understood that whilst I have described my motor as specially
serviceable for operating clocks, 1 do not limit myself to this field of application as
it may be used to operate any other mechanism where a slow movement might be
found desirable.
Having thus described my invention, what I claim as new and desire to secure
by Letters Patent is
+
:-
1. The combination of a pendulum, a slide adapted to reciprocate in fixed
bearings when the pendulum vibrates, an electro-magnet for imparting accelerating
impulses to the pendulum, and a circuit closing contact mounted on the slide to open
the magnet circuit after each impulse has been imparted.
2. The combination of a pendulum, a slide adapted to reciprocate in fixed
bearings, projections from the slide into the path of vibration of the pendulum on
both sides thereof, an armature fixed to the pendulum, an electro-magnet for
creating a magnet field in the path of the armature, and a circuit closing contact
mounted on the slide to open the magnet circuit after each accelerating impulse
imparted by the magnet.
3. The combination of a pendulum, a slide provided with journals sliding on fixed
bearings, pins 21, 22 at the sides of the pendulum, a circuit closing contact mounted
on the slide, electro-magnet 4 and armature 8.
4. The combination with a pendulum of a circuit closer periodically actuated
thereby, an electro-magnet controlled by the circuit closer, an armature co-operating
with the magnet for imparting periodical accelerating impulses to the pendulum,

page_text: and means for adjusting the magnet with relation to the armature so as to make the
impulse stronger or weaker.
5. The combination of a pendulum, pivoted arm 9, an electro-magnet and
armature for imparting periodical accelerating impulses to the pendulium, and a
circuit closer controlled by the pendulum for opening and closing an electric circuit
including the magnet.
6. The combination of a pendulum, a sliding contact 14, and brush 15 adjustable
in the direction of movement of the contact.
7. The combination of a pendulum supported by a spring offering by its tension
resistance to acceleration and an electro-magnet controlled by a circuit closer
actuated by the pendulum for imparting periodical accelerating impulses to the
lower end of the pendulum.
8. The combination of a pendulum provided with elastic strip 3 for offering a
resistance to acceleration by its tension, rod 5, and an electro-magnet for giving
periodical accelerating impulses to the pendulum.
LEON POPE.