LMPROVEMENTS IN AND CONNECTED WITH CARBONS FOR ELECTRIC ARC LIGHTING
Year: 1884

page_text: COMPLETE SPECIFICATION.
I, WILSON HARTNELL, of Benson's Buildings, Park Row, Leeds, in the County
of York, Electrical Engineer, do hereby declare the nature of my Invention for
LMPROVEMENTS IN AND CONNECTED WITH CARBONS FOR ELECTRIC ARC LIGHTING
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:—
In ordinary electric arc lighting the ends of the lengths of carbon which are
fixed in and grasped by the metallic sockets or holders provided for the purposo
are necessarily left unconsumed, and being practically valueless are unavoidably
wasted. These wasted ends often form as much as twenty per cent. of the length
burnt. The object of my Invention is to introduce a systematic method whereby
the entire length of a carbon may be consumed from end to end, (and this without
risk of damage to the lamp sockets or holders alluded to) and so bring about
by this economy a reduction in the cost of arc lighting. I accomplish this as
follows: Firstly-By taking these unconsumed lengths and systematically joining
them together one short length on to the end of another, and so on, or one short
length on to the end of a new long length, so that they shall form collectively
another carbon of such a required length as shall enable it to be satisfactorily used;
the remaining end of this latter length being in turn treated in a like manner.
Secondly by manufacturing new lengths of carbon with suitably formed ends
such as will permit the remaining unconsumed end of one carbon to be joined or
fitted to the end of the next length, and so on with its remaining end, thus allowing
the whole of a series of carbons to be systematically used up to the last remaining
end. Thirdly-by using sockets, unions, or clips, whereby any remaining lengths
of carbons-whether specially prepared or not--may bo so joined, systematically,
as to be likewise advantageously consumed; and also by using other shapes and
forms of unions, such as dowels, dovetails, and other pieces having both ends
shaped alike for systematically joining up lengths having both of their ends also
prepared and shaped alike and of the required form to suit these unions.
My Invention will also overcome a great disadvantage which presents itself to
those who endeavour-for the obvious economy-to burn their carbons low and
near to the lamp sockets. These lamp sockets being easily burnt and spoiled by
the great heat evolved when the light is burning. This risk of damage is now
[Price G1

page_text: uncalled for, as the remaining end of one carbon can be joined to and used up with
the next carbon.
A further benefit also results from the fact that a lamp fitted with one pair of
carbon holders and their accompanying gear will now possess an advantage hitherto
appertaining only to lamps fitted-at a greater cost-with double pairs of holders
and their gears. The advantage of a lamp with double pairs of carbons has hitherto
to a great extent lain in its being able to use up-as far as the holders permitted―
a partially consumed pair of carbons such as might last one or two hours only, the
illumination then being continued by the other pair of carbons coming into action
and prolonging the light for the required number of hours. Now by my plan a
pair of carbons of sufficient length (whether made up of two or more shorter lengths
does not signify) can always be arranged by the workman in charge of the lamps
previous to the lighting up, so that the ordinary length of time that a full length
of carbon will last out may always be relied upon for a continuous light when
required.
In carrying out my Invention I proceed as follows, first-dealing with the old
ends of carbon-I take them and drill, bore, saw, file or otherwise make a suitable
cavity or dovetail in or at the end of each length and at the other end I cut or
form a corresponding projection to suit that made at the first montioned end;
I then fix these ends together, one length on the end of another, & so on, as
shown on the accompanying Drawing at B. and use them in such combined lengths
as may suit the lamp: or one or more short lengths make be fixed to the end of a
new full length specially prepared as explained below. Varieties of joints are
shown at A. B. C. D.
The second part of my Invention relating to the forming or making of new
carbons with suitable ends is carried out in a manner similar to that described.
above, except that for the sake of cheapness I profer to form the special ends in the
first place by moulding them or otherwise compressing the ends when the carbons
are originally made. E may be taken as representing such a length of carbon
with specially prepared ends, whilst A, B, C, D, again show varieties of forms of
joints.
The third part of my Invention-which is the natural outcome of the others-
consists in using sockets, unions, clips, dowels, and other connecting forms, for
joining purposes. In making unions or sockets I prefer to make them of carbon
slightly coned at each end-the narrow ends of the cones meeting in the centre, as
shown at F. G. H. Such a socket may be left rough, or be bored out, or screwed,
and the ends of the carbons may be filed, turned, or screwed to suit. The slight
taper of the cones will assist two carbons of unequal diameters in bedding and
fixing themselves. Clips may be made of very thin metal-a spiral form is shown
at 1, and at K another variety, made out of one piece of metal, which will
accomodate different diameters of carbon at each end. As metal clips will be
melted it is necessary to arrange that no harm is done-Such clips can be used
only in the lower carbons and each joint must stand on a square end so as not to
fall over when the clip melts-I do not recommend this class of joint, although a
thin dowel as at P. would improve it. Dowels may be made of carbon, wood,
metal, and other materials-the ends of the lengths of carbon being drilled, bored,
screwed or cut to suit-Varieties are shown at L, M-N, O, P-The other forms of
connections are best made of carbon, suitably shaped-an example is given at Q-
they have an advantage in cases where it is desired to have both ends of the
lengths of carbon shaped alike-Paper sockets as shown at R,-can be made
very thin, but as they would be non-conductors care would have to be taken to
bring the ends of the carbons in contact, or a conducting cement or powder used to
fill up the space; indeed it is essential that all forms of joints have a good &
clean contact so as to conduct the electricity properly.
With regard to the cementing of the ends of carbons together-which would
have to be done with a conducting cement-such a course is not in my opinion
likely to give satisfaction, owing to the great heat brought to play on the carbon

page_text: when incandescent, but cement will prove useful when employed for strengthening
the joints for the more convenient handling of a length of carbon when built up of
several pieces.
All joints that are not actually interlocked should only be used in the lower
carbons. I do not look with favour upon joints that bulge outward-such as the
carbon unions at G. H. as such may vary the light at the time when the larger
mass of carbon is in action.
I wish it to be understood that I do not confine myself to any particular modo
of joining the carbons, but I would point out that such a joint as shown at A, or a
doweled joint as shown M. O. will give satisfactory results both in top and
bottom carbons, as the screws will hold them from falling apart, and the contact
will prove satisfactory for conducting the electricity. The Drawing shows the
general principle and form of the mode of joining-Varieties could be made in
great numbers.
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
1. The joining together of the ends of lengths of carbon-(whether partly
consumed or not) systematically, with the object and for the purpose described.
2. The shaping of the ends of lengths of carbon (whether partly consumed or
not) systematically-substantially in the manner and for the purpose as herein.
before described and as shown on the Drawing.
3. The making of new carbons with their ends suitably shaped, systematically,
substantially in the manner and for the purposo as hereinbefore described and as
shown on the Drawing.
4. The use of sockets, unions, clips, dowels, and other connecting pieces for the
purpose of joining up lengths of carbon systematically with the object and for the
purpose herein before described.
5. The making of sockets, unions, clips, dowels and other connecting pieces, of
carbon, metal, wood, paper and other like substances-for the purpose of joining up
lengths of carbon systematically, substantially in the manner and for the purposo
as hereinbefore described and shown on the Drawing.
Dated this Ninth day of June 1884