Improved means for Supplying Electric Current to Electrically Operated Time Keeping Mechanism.
Year: 1897

page_text: Improved means for Supplying Electric Current to Electrically
Operated Time Keeping Mechanism.
We, ALWYN WALTER STAVELEY, ISAAC HARDY PARSONS, and THOMAS JOHN
MURDAY, all of Faraday Works, Braunstone Gate, Leicester, in the County of
Leicester, Electrical Engineers, do hereby declare the nature of this invention to be
as follows;-
-
Our invention relates to improved means especially applicable for use in con-
nection with electrical time keeping mechanism for supplying electric current for
operating a pendulum or balance wheel.
According to our invention the pendulum or balance wheel is operated by an
electro magnet in the circuit of which we introduce a pair of contacts one of which
is hinged or adapted to spring. Upon the rod of the pendulum is pivoted so as to
swing very freely a trip piece advantageously of wedge or V-shape which normally
hangs vertically. On the movable contact is a block having a notch in which the
end of the trip piece can engage, the said trip piece and block being arranged in
such relation to each other as regards length and thickness, that when the pendulum
is in its vertical position and the end of the trip piece is in the notch of the block
the contacts will be closed together to complete the electric circuit through the
magnet. The length of the said block is such that under the normal swing of the
pendulum the trip piece will completely pass over it without moving the contact
the said trip piece swinging upon its pivot to permit of its passing the block.
When, however, the swing of the pendulum falls below a certain limit the said
trip piece will not clear the block whereby on the return swing of the pendulum the
trip piece will slide along the top of the block until its free end enters the notch
whereupon the pendulum and trip piece (which form a kind of toggle) are moved
into alignment and so depress the block to complete the electric circuit. This
imparts a fresh impulse to the pendulum through the medium of the electro-magnet,
and it can thus be kept working for an indefinite period, so long as current is
supplied.
Improved means for Supplying Electric Current to Electrically
Operated Time Keeping Mechanism.
We, ALWYN WALTER STAVELEY, ISAAC HARDY PARSONS, and THOMAS JOHN
MURDAY, all of Faraday Works, Braunstone Gate, Leicester, in the County of
017

page_text: Leicester, Electrical Engineers, do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
Our invention relates to improved means especially applicable for use in con-
nection with electrical time keeping mechanism for supplying electric current for
operating a pendulum or balance wheel.
According to our invention the pendulum or balance wheel is operated by an
electro magnet in the circuit of which we introduce a pair of contacts one of which
is hinged or adapted to spring. Upon the rod of the pendulum is pivoted so as to
swing very freely a trip piece advantageously of wedge or V-shape which normally
hangs vertically and on the movable contact is a block having a notch in which the
end of the trip piece can engage.
To enable our invention to be fully understood we will describe the same by
reference to the accompanying drawings in which:-
Figure 1 is a front elevation showing an arrangement for operating a pendulum
according to our invention; and,
Figure 2 is a section of the same on the line 2-2 Figure 1:
Figures 3 and 4 are views of some of the parts shown in Figure 1 but in different
positions.
Figure 5 is a sectional side view shewing the arrangement of our invention when
halance wheel is employed;
Tigunes and 7ational plan of the sains the sections luing taken respect-
ively on the line 66 and 7-Figure 5;
Similar letters of reference indicate corresponding parts in the several figures.
a is the pendulum which as shown is carried by an arbor b supported in the
back or base plate e and in the bracket d affixed thereto as shown in Figures 1 and 2.
e is the electro magnet for operating the said pendulum the armature e¹ of the
magnet being connected with the pendulum by a hook 3, the said magnet receiving
its current from any suitable generator, say the battery through the wires g, h
in one of which, say the latter, are the spring contacts i, the normal tendency of
which is to retain the circuit open or broken, an adjusting screw k serving to regulate
the upward movement of the contact j.
is the pendant or trip piece which is pivoted upon the rod of the pendulum so as
to swing very freely and m is the block notched at m' to receive the free end of the
trip piece and fixed upon the contact spring j.
The said trip piece and block are arranged in such relation to each other as
regards thickness that when the pendulum is at rest and the end of the trip piece is
in the notch of the block the contacts will be closed together to complete the
electric circuit through the magnet e. The length of the block m is such that with
a normal arc of oscillation of the pendulum the trip piece will pass right over the
said block m without moving the spring ; but that when the swing of the pendulum
falls below a certain limit, the said trip piece will not clear the block but rest
upon the top of the same as shewn in Figure 4 so that, on the return swing of the
pendulum in the direction of the arrow in the said figure, the said trip piece will
slide along the top of the block until its free end enters the notch m', when the said
spring will be pres-rd down in a manner which will be readily understood by
reference to Figures 1 and 2 whereupon the circuit of the battery will be completed
through the magnet e which will impart an impulse to the pendulum. This impulse
is sufficient as a rule to cause the said pendulum to make several oscillations
before the arc of oscillation becomes short enough to again cause the trip piece to
rest upon the top of the block as shewn in Figure 4. The number of oscillations
which the pendulum makes without a fresh impulse will be dependent upon the
amount of work which the pendulum has to perform so that if this work is variable
the battery circuit will be completed more often than if the work is light so that
practically the oscillation of the pendulum is invariable notwithstanding variations
of the load. Of course if the load upon the pendulum is constant as, for instance

page_text: would usually be the case in an electric clock, the number of oscillations which the
pendulum will make after each electric impulse will be uniform. The object of
the notch m² in the block m is to ensure that when the trip piece is in contact with
the said block as shewn in Figure 4, it shall not for any reason slide along and off
the same without depressing it.
Any suitable means may be employed for converting the oscillating motion of the
pendulum into rotary motion. As shewn in Figures 1 and 2, a pin n carrying a
roller on the pendulum is designed to operate against an inclined cam surface o upon
an arm o pivoted at o³. This arm of at one end carries a spring pawl p designed
to engage with the teeth of a ratchet wheel 7 carried on an arbor or shaft
other end of the said arm o³ carrying a counterweight r.
the
With this arrangement it will be understood that the length of the arm o¹ and the
ratchet teeth being properly proportioned each oscillation of the pendulum in one
direction will allow the pawl to drop whilst the oscillation in the reverse direction
will cause the rotation of the ratchet wheel a distance of one tooth.
It will be obvious that the motion of the shaft 7 can be utilized in any desirable
manner.
The arrangement of our invention in connection with a balance wheel is illus-
trated in Figures 5 to 7, in these figures is the balance wheel which is mounted
upon the arbor t; u is a hair spring in connection with the said balance wheel
and is a lever pivoted ate and having one end bifurcated and a pin w upon the
balance wheel projecting into the bifurcation, so that as the balance wheel oscillates
an oscillatory motion will be imparted to the lever ; the other end of the said
lever vis provided with pawls, which work in connection with a ratchet wheel a¹
the motion of the spindle of which is utilized in any desired manner.
pawls, and the ratchet wheel are similar in construction to the ordinary
anchor escapement but operate in the reverse manner, that is to say, the anchor
instead of receiving its motion from the wheel as is the case in the escapement
transmits motion to the wheel.
These
The armature e is fixed to the arbor t of the balance wheel between the poles
of the magnet e in a well known manner so that when the magnet is momentarily,
energized the armature will be attracted to move the balance wheel and coil the
hair spring which will react.
The contacts i, j are arranged in the circuit of the magnet e as hereinbefore
described the latter contact having fixed to it the block m which is similar to the
black m herein before described except that it is of segmental shape as clearly
shewn in Figure 7.
The trip piece depends from an arm fixed to the boss of the balance wheel
in such a manner that as the latter oscillates the said trip piece will slide over the
block m.
It will be understood that so long as the oscillations of the balance wheel are
sufficient to carry the trip piece / over the block m the contacts i, j will not close
the circuit but that when the oscillations of the balance wheel are shortened to such
an extent that the trip piece does not pass over the block m the contact j will be
depressed in the manner hereinbefore described.
Ilaving now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:-
1. The improved means for supplying an electric current to electrically operated
time keeping mechanism wherein a trip piece such as 7 is arranged in conjunction
with an oscillating pendulum or balance wheel and with a pair of electric contacts
in such a manner that when the oscillations of such pendulum or balance wheel
have a certain amplitude, no contact is made, but that, when the amplitude of the
oscillations falls below this point, the contact is completed, whereby a uniform speed
of oscillation with variable loads can be obtained, substantially as described.
2. In electrical time keeping mechanism, the combination of a pendulum, a

page_text: trip piece pivoted to the said pendulum, and a pair of contacts normally open but
adapted to be closed or pressed together when the trip piece bears upon the contact
and is in alignment with the pendulum, substantially as described.
3. The improved mechanism for supplying current to electrically operated time
keeping mechanism, substantially in the manner hereinbefore described and illus- é
Irated in the accompanying drawings.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.