Improvements in and connected with Electric Arc Lamps.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in and connected with Electric Arc Lamps.
JOHN OWEN GIRDLESTONE, of 16, Davies Street, Berkeley Square, in the County
of London, and CARL FREDERIK GRIMUR THORKELIN, of 29, Marriott Road, Toll-
ington Park, in the County of London, Electrical Engineers, do hereby declare the
nature of this invention to be as follows:-
1. A central tube A passing into the body of the lamp & containing the upper
carbon holder B which slides preferably on rollers in this tube.
2. A method of attaching the globe to the bottom plate of the lamp so that the
globe fitting forms a guide for the upper carbon as shown in C.
3. A hinged or detachable bottom carbon holder D.
4. The particular construction & arrangement of the mechanism in the lamp
enabling it to burn either on alternating or continuous current circuits & for
series or parallel & consisting of a brake wheel controlling the feeding of the
carbons & a spring drum for automatically adjusting the length of the metallic
suspension for the carbon holder or holders as shewn in E.
Detail this 26th day of January 1898
J. O. GIRDLESTONE,
C. THORKELIN.
Improvements in and connected with Electric Arc Lamps.
JOHN OWEN GIRDLESTONE, of 16, Davies Street, Berkeley Square, in the County
of London, and CARL FREDERIK GRIMUR THORKELIN, of 29, Marriott Road, Toll-
ington Park, in the County of London, 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 ascertained in and by the following statement;-
The drawings No. 1 and 2 filed with the Provisional Specification and the addi-
tional drawing No. 3 herewith represent an arc lamp embodying our improve-
ments in accordance with the following description:
In order to keep down the length of the lamp the upper carbon holder is made
to slide in a tube, A which passes into the body of the lamp and forms an enclosed
guide for the carbon holder. The globe is held against a lower plate which also
forms a guide for the upper carbon and tends to prevent the interior of the lamp
becoming unduly heated, shown in C drawing No. 1. In order to easily recarbon
the lamp the bottom carbon holder D is so arranged that it works on a hinge and
can be swung to one side to allow the globe to be removed or the method shown on

page_text: drawing No. 3 may be employed consisting of two rods fixed to the lower plate C
and insulated from it and passing down inside the globe to the bottom carbon
holder which is fixed to the rods or with them forms part of one casting; the
globe itself is supported from the outside by means of a spiral spring or otherwise
which presses the globe against the plate C with sufficient force to hold it firmly
without breaking the glass.
The particular arrangement of the lamp is such as to allow it to be used (with
the usual modifications in the winding and iron cores) for either alternating or
continuous current and having a differential regulation consisting of a series and
a shunt coil controlling separate cores it may be used for either parallel or series
burning to suit requirements.
A spring drum is preferably fixed on the spindle carrying the brake wheel and
the spring is fastened with one end to the drum whereas the other end of the
spring is fixed to the supporting bracket carrying the spindle, by this means the
spring always exerts a certain torque on the spindle tending to turn the spindle in
one direction only, and in this way it acts as a counterweight for the upper carbon
holder and also automatically winds up the metallic cord by which the carbon
holder is suspended.
Or the spring drum may be loose on the spindle and connected to it by means
of a pawl, which falls into a ratchet wheel fixed on the spindle, this would secure
the regular winding up of the metallic suspension cord when the lamp is recarboned
even in case the brake wheel did not move quite freely as might happen if the
shunt coil was more powerful than the main coil.
In order that our invention may be readily understood we will now describe the
same with reference to the accompanying drawings.
Fig. 1 is a longitudinal section through the lamp Fig. 2 is a cross section through
centre of spindle R & Fig. 3 is a section showing another method of attaching the
globe to the lamp.
In Figs. 1 & 2 P & P are the top & bottom plates of the lamp. S¹ & S² are
the shunt & series solenoids respectively with iron cores K' & K³ which are con-
nected by means of pins to the ends of the lever L the lever itself being pivotted
as shown to the centre tube A. The connecting link M joins the rocking lever L
to the brake lever N, at suitable points on each side of the pivot on which N moves
are fixed the ends of the brake strap which may be a piece of chain or other suit-
able material. W is a weighted lever moving freely round the spindle R & forming
at the same time a pivot for the brake lever N. The brake drum Q is attached
rigidly to the spindle R. This spindle is carried by 2 supports V and V1 between
centre points as shown. The support VI also carries the sleeve Y on which the
spring drum E turns as explained hereafter.
The centre tube A is so constructed that the positive or upper carbon holder B
slides freely in it, 3 rollers T are fitted at the upper end to minimise friction. To
the upper end of the carbon holder a flexible cord is attached which passes over
the pulley U & then down to the spring drum E round which it is taken & secured.
This spring drum E contains a coiled spring tending to wind the cord round the
drum against the weight of the upper carbon holder B, the latter however is made
of sufficient weight to overcome the pull of the spring & to cause the upper carbon
to fall on the lower until drawn away by the action of the current as explained
hereafter. A ratchet wheel J is fixed to the spindle R & drives the spring drum E
by means of the pawl O which is fixed to the drum. The drum E turns on the
fixed sleeve Y one end of the contained spring being fixed to this sleeve & the
other end to the drum itself. The carbons are shown at X & X. The globe is
attached to the lamp in the manner shown in Fig. 1. The part D is a stirrup
pivotted at the 2 points P3 P4 & having removable pins as shown attached by a
short piece of chain to the supports which are insulated from the bottom plate pa
as shown. When the bottom carbon X & the two pins are removed the stirrup
can be swung to one side & the globe with the guide piece G & attachment
springs F can be removed. The disc C forms the lower guide for the upper carbon

page_text: The
& the piece H serves to close the opening in the bottom of the globe. Fig. 3
shows another method of attaching the globe in which is the bottom plate of
the lamp. R, R¹ are studs screwed into the bottom plate & nutted or otherwise
attached to the guide plate C through which the upper carbon works.
rods A A carrying the lower carbon holder are insulated from C as shown. The
knob K with spring & top piece attached are connected to the lower carbon
holder H by a bayonet joint. By turning the knob & so unlocking the bayonet
joint the knob, spring & top piece can be withdrawn & the globe detached.
Having now described the various parts of the lamp with reference to the draw-
ings we proceed to describe the way in which the lamp works.
When the lamp is at rest the two carbons are touching one another, the weight
of the upper carbon holder being so adjusted as to safely overcome the friction of
the various parts, and also the tension of the spring.
When a current is passed through the lamp the brake wheel with the spring
drum is turned a short distance by means of the iron core being drawn into the
main solenoid until a balance is obtained between the main coil and the shunt, the
automatical controlling or feeding of the arc takes place in the usual way—as
the arc gets longer the pull on the shunt core increases, this releases the brake
wheel and the carbons fall together until balance between the two coils is restored.
Having now particularly described and ascertained the nature of our said in-
vention, and in what manner the same is to be performed, we declare that what
we claim is:-
-
1. In an arc lamp a central tube A passing into the body of the lamp and con-
taining the upper carbon holder B which slides preferably on rollers in this tube.
2. In an arc lamp a method of attaching the globe to the bottom plate of the
lamp so that the globe fitting forms a guide for the upper carbon as shown in C
or by preference as shown in drawing No. 3.
3. In an arc lamp a hinged or detachable bottom carbon holder 1).
4. The particular construction and arrangement of the mechanism of an arc
lamp as shown in drawings No. 1 and No. and consisting of a brake wheel con-
trolling the feeding of the carbon and a spring drum for automatically adjusting
the length of the metallic suspension for the carbon holder or holders as shown
in E.