Apparatus for Automatically Indicating Loss or Diminution of Current in Electric Circuits.
Year: 1891

page_text: Date of Application, 20th Feb., 1891
Complete Specification Left, 20th Nov., 1891-Accepted, 20th Feb., 1892
PROVISIONAL SPECIFICATION.
Apparatus for Automatically Indicating Loss or Diminution of
Current in Electric Circuits.
1, WILLIAM CRUYT, Managing Director of the Société Anonyme des Horloges
et Pendules Electriques, of St. Nicolas, Wacs, in the Kingdom of Belgium, do
hereby declare the nature of my invention to be as follows:-
My invention has for its object, to provide simple and reliable means for
automatically indicating when the current in an electric circuit falls below an
allowable minimum strength, in consequence of bad contacts, or approaching
exhaustion of the battery, or through any other cause, and this long before the
current has become insufficient to perform its normal function.
For this purpose, I employ an electro-magnet or magnets excited by the current
which is to be kept approximately constant; two armatures controlled by the
said magnet or magnets, and provided with resistances which can be varied at will
and independently of each other; a pair of ratchet wheels mounted close together on
the same axle, but adapted to turn independently of each other, one of the said
wheels having parts of its face painted red or with other bright colour, while the
other wheel has perforations corresponding in number and size to the coloured
parts of the first wheel, so that in certain relative positions of the wheels, the said
colour can be seen through the perforations: a pair of ratchet pawis secured to the
said armatures and operated by the same in such a manner, that the pawl which is
attached to the first armature acts on the first tooth wheel, while the pawl which
is operated by the second armature acts on the second tooth wheel, and both tooth
wheels are turned in the same direction.
As long as the two armatures vibrate in unison, the two tooth wheels turn at the
same speed, and there is no relative motion between the same; but if one of the
armatures ceases to operate, because the current has become insufficient to overcome
its resistance, there will be a relative motion between the two wheels, so that sooner
or later the coloured parts of the lower or back wheel will become visible through
the apertures of the upper or front wheel.
The variable resistance is preferably a helical spring attached at one end to the
armature and at the other to a set screw, the turning of which changes the tension
of the spring, and the motion of each armature lever produced by the spring in
opposition to the magnet, is limited by another set screw. The springs belonging
to the two armatures are of unequal strength, or at unequal tension, so that if the
current decreases, the armature which is connected with the stronger spring will
cease to turn the toothed wheel, while the other continues to operate.
In order to give an electric alarm signal, when one of the two wheels has stopped,
while the other continues to turn, the lower wheel has a hub of insulating material,
which carries a metallic ring provided with a radial arm, and the upper wheel has
a corresponding arm, extending backward through a slot of the lower wheel in such
a manner, as to meet the said radial arm when one of the wheels turns relatively to
the other, thus completing the electric circuit of an alarm bell which passes
through the base plate of the apparatus to the upper wheel, through the two arms into
the metallic ring and thence through a tangent spring to a terminal or binding
post mounted on the base plate, but insulated from the same.
The apparatus may be rendered more or less sensitive by varying the tension of
the two resistance springs mentioned above.
"nit: nut 1
CL1001
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicant.

page_text: Apparatus for Automatically Indicating Loss or Diminution of
Current in Electric Circuits.
I, WILLIAM CRUYT, of St. Nicolas, Waes, in the Kingdom of Belgium,
Electrical Clock-maker, 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:-
The object of this apparatus is to indicate any decrease in the strength of an
electrical current performing known functions in a given circuit, such decrease of
strength being due to defective contact, to wear, or to any other cause, and the
apparatus is particularly adapted to instantly notify any such decrease of strength,
however small, the moment it takes place, and long before the current becomes
actually insufficient to answer its purpose.
The apparatus consists of an electro-magnet A. included in the circuit to be
controlled and of an armature B B₁ divided into two parts or sections each of which
carries and operates a pawl C C which acts upon one of a pair of ratchet
wheels D D Fig. 2. The pawl C serves to move the wheel D in the direction
indicated by the arrow while the pawl C in rising imparts motion in the saine
direction to the wheel D. Two other pawls E E' Fig. 2 are adapted to prevent
the ratchet wheels D D' from rotating in the opposite direction. Two springs FF1
draw both halves of the armature, or in other words, the two armatures against
two screws H and H in a manner which depends on the effect to be produced as
will be more fully explained further on. Two screws G G control the tension of
the springs FF, the spring F being submitted to a less strain than the spring Fl
for a purpose presently to be stated. Two circular openings S situated diametri-
cally opposite each other in the front ratchet wheel D expose parts of the other
ratchet wheel D' to view and upon this latter wheel are marked two preferably red
circles or circular spots T which may or may not coincide with the openings of the
front wheel D according to the effect produced by the current.
The operation is as follows:-
So long as the current is sufficiently strong to perform its proper functions in the
circuit, the two halves of the armature B B are simultaneously attracted and the
two wheels D D' both advance in the same direction the distance of one tooth so
that the openings S and the circles T retain their relative positions to each other
without any change.
Should however the current become so weak as to make the operation of the
devices it is to act upon insecure the tension of the spring F being greater than
that of the spring F the armature section B retained by this latter spring F will
alone be attracted until it reaches the pole of the electro-magnet A and the pawl C
rising when this armature is released by the cessation of the passage of the current
and through the electro-magnet will operate the ratchet wheel D¹. From this
moment the same operation will take place at each contact occurring in the circuit
the ratchet wheel D' turning in the direction of the arrow behind its companion D
which remains stationary, so that the two red circles of the wheel D₁ become
partly visible through the circular apertures S S.
By the time that the wheel D₁ has moved so far that its pin N impinges against
the pin P Fig. 2 of the other wheel D which is stationary, the circles or discs T
will have come fully into coincidence with the openings S which must be regarded
as a sign or signal that the batteries should be inspected and re-adjusted as required,
while a signalling contact will at the same time come into operation in a secondary
circuit passing through the body of the apparatus the wheel D the pin P and the
pin N secured to the insulated socket K whence the current will flow through the
spring L which is in contact with the said socket K but insulated from the main
body of the apparatus at R. The tension of the springs and accordingly the

page_text: degree of resistance of the armatures B B' may be adjusted at will so that the
electrical sensitiveness of the whole apparatus may by this means be varied as
required. In practice it is advisable to take immediate measures to re-adjust any
weakness of the battery thus discovered so as to allow as long a space of time as
possible to elapse between the commencement of such weakness and the moment
when the insufficiency of the current makes itself inconveniently felt so as to obviate
actual defects in the operation which when found to be due to the weakness of the
current it might then be too late to remedy. It will be understood that owing
especially to the method of adjustment by means of springs which we have
adopted this result is fully attained.
Though the armature before described has been referred to as one armature
divided into two halves and operated by the same electro-magnet it is obvious that
two separate armatures each operated by its own electro-magnet may instead be
employed.
Haring now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed 1 declare that what
I claim is :-
1. The combination with one or more electro-magnets and two armatures whose
resistance to the attraction of the electro-magnets is adjustable of two toothed
wheels independent of each other but arranged side by side and one of which bears
readily discernible marks or signs while the other is provided with openings through
which these marks are adapted to appear and of pawls fitted to the said armatures
each operating one of the two toothed wheels all substantially as and for the
purpose described.
2. In apparatus such as described the combination of two wheels or discs such
as D D the front or visible one of which is provided with one or more openings
through which a signal or indication governed by the back or obscured wheel or
dise may be viewed substantially as described and illustrated in the accompanying
drawings.
3. In apparatus such as described the employment of springs such as F F and of
two adjustable stops such as H H against which the said springs are adapted to
draw the two armatures substantially as described and illustrated in the accom-
panying drawings.
4. In apparatus such as described the combination with the wheels D D' of pins
such as N and P intermediate insulated socket such as K and spring such as L
pressing upon the socket K and being insulated from the main body of the apparatus
all substantially as and for the purposes described and illustrated in the accom-
panying drawings.
Dated this 20th day of November 1891.
W. P. THOMPSON & BOULT,
Agents for the Applicant.