IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by John Henry Johnson at the Office
of the Commissioners of Patents on the 29th October 1880. A communi-
cation from abroad by Albert Berjot, of Paris, in the Republic of France.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN ELECTRIC LAMPS." A communication from
abroad by Albert Berjot, of Paris, in the Republic of France.
This Invention relates to electric lamps, and it consists chiefly in the employment
of a regulating apparatus arranged in the form of a parallelogram with flexible
spring joints in combination with a number of pairs of carbons which are consumed
in succession, the current being automatically diverted into a fresh pair when the
pair in use for the time being has been consumed. The Invention further relates
to a device whereby the loss of weight consequent on the consumption of the
carbons is compensated for automatically, also to an arrangement for shutting off
the current from the apparatus when the last pair of carbons has been consumed,
and to an electro solenoid or device for regulating the length of the arc when
several apparatus are working on one circuit. This apparatus is capable of working
with an ordinary electro magnet placed on the circuit without the intervention of
a branch current.
In carrying out this Invention, the essential part of the apparatus is composed
of a parallelogram, consisting of two horizontal bars carrying the mechanisin for
actuating the carbons, the said bars being jointed to two vertical bars by blades
springs similar to the springs ordinarily employed for suspending clock pendulums.
By this arrangement a maximum amount of sensitiveness is obtained, the system
being enabled to work without friction and whilst at the same time it possesses
perfect rigidity.
When points or centres are employed for forming the joints as in the arrangement
heretofore adopted, it is not possible to adjust the points so as to prevent all play
of the parts without destroying the sensitiveness of the apparatus, moreover as
the points continually wear away it becomes impossible to obtain an accurate
adjustment, and the amount of play allowed increases so rapidly that the points of
the carbons soon cease to be exactly opposite each other.

page_text: The apparatus as constructed according to this Invention comprises the following
parts, viz.:-
1st. Racks for effecting the descent of the upper carbons.
2nd. A train of four wheels and pinions for obtaining a slow and regular
descent of the carbons or total suspension of motion as required. The motion or
stoppage as well as the first soparation of the carbon points is obtained by the
ascent or descent of the movable part of the parallelogram (to the extent of about
one tenth of an inch, which is acted upon by an electro magnet on the circuit, the
separation of the carbon points as well as the putting in and taking out of gear
being effected solely by this magnet through the intervention of its armature.
The electro solenoid only comes into action when the arc becomes too long.
The said electro solenoid consists of the following parts, viz.
1st. A coil composed of wire of such diameter and length that its resistance is
equivalent to the resistance of the longest arc employed.
2nd. A fixed core of soft iron the length of which is equal to one quarter the
length of the coil.
3rd. A movable core of soft iron forming part of the movable part of the
parallelogram, and filling up the remaining space in the centre of the coil with the
exception of a short interval separating it from the fixed core to which it acts as an
armature.
The movement or the stoppage of the wheelwork is obtained by means of a fixed
stop placed above the last wheel of the train hereinbefore referred to, and which
engages with and stops the teeth of this wheel, or allows them to pass according to
the position of the movable part of the parallelogram.
When a pair of carbons has been consumed the current is automatically diverted
and caused to pass in a fresh pair of carb as by means of a lover suitably pivotted
and arranged at the back of and betweè.. two racks corresponding to two pairs of
carbons to be consumed in succession. This lever carries two projections at its
lower extremity; one of these projections is smooth and bears against the back of
the rack connected with the pair of carbons to be first consumed, whilst the other
projection is provided. with teeth which engage with the teeth of the rack
corresponding to the pair of carbons to be next consumed. The system thus
arranged allows the first rack to descend by its own weight and actuate the train
of wheels, the motion of the said wheels being at the same time controlled by the
electro magnet on the circuit through the intervention of its armature.
When in consequence of the consumption of the carbons the first rack has
descended nearly to the bottom of its stroke, a recess provided near its upper
extremity comes opposite the smooth projection on the lever herein before referred
to, which projection immediately falls into the said recess, and at the same time
allows the toothed projection on the same lever to disengage itself from the teeth
of the second rack, which is then free to descend, and descends simultaneously with
the first rack until the latter reaches the bottom of its stroke and comes in contact
with a stop. The second rack then descends alone.
The arc produced between the two first carbons then becomes increased to. a
certain extent, whereupon the branch current begins to act and causes the train of
wheels to run down rapidly until the second pair of carbons come in contact with
each other, and the arc is then produced by the latter pair in lieu of by the first
pair, which now offer greater resistance to the passage of the current. The
apparatus continues in this condition until the second pair of carbons has been
consumed, whereupon a third pair is brought into action in a similar manner, and
so on in succession according to the number of pairs of carbons in the apparatus.
When the last pair of carbons has been consumed the apparatus is cut off from
the circuit automatically by means of a spring carrying a smooth projection
similarly arranged to the smooth projection herein before referred to on the lever at
the back of the racks, which spring serves to establish a direct communication
between the two binding screws of the apparatus so as to cut the lamp off from
the circuit without requiring any attention.

page_text: After each pair of carbons has been consumed, the consequent loss of weight is
compensated for by means of a small ball of lead provided at the extremity of a
horizontal lever suitably pivotted and resting at one extremity upon a bracket on
the stationary part of the parallelogram in the same plane with the joints. When
each rack reaches the end of its stroke one of its extremities comes in contact with
the other extremity of the lever and draws it down, whereby the ball is elevated
and its weight, which with that of the lever corresponds to that of the carbons
which have been consumed, is then supported by the movable part of the
parallelogram whilst the remaining carbons are being consumed. A similar
arrangement is provided for each pair of carbons, so that after all the carbons have
been consumed the movable part of the apparatus is of the same weight as when it
was provided with carbons.
The carbon holders consist of copper cylinders fitted at one extremity into holes
of the same diameter, carried by the lower extremities of the racks for the upper
carbons, and by the lower extremity of a suitable fixed rod or support for the
lower carbons. These cylinders are formed internally of such dimensions as to admit
of the carbons being inserted in position with facility, the said dimensions being
modified to suit the different sizes of carbons employed. Springs fitted in a suitable
recess in the sides of the cylinders press upon the carbons to ensure proper contact