Improvements in Electric Arc Lamps.
Year: 1894

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 18 of the Patents, &c., Act, 1883), as allowed by
the decision of the Chief Examiner of the 29th day of August 1896.
Date of Application. 7th Dec., 1894
Complete Specification Left, 5th Oct., 1895-Accepted, 9th Nov., 1395
PROVISIONAL SPECIFICATION.
Improvements in Electric Arc Lamps.
I, JAMES BROCKIE of 12 Tyson Road, Forest Hill, in the County of Kent,
Electrical Engineer do hereby declare the nature of this invention to be as
follows:-
This invention relates to certain improvements in the brake mechanism of
electric arc lamps, when such mechanisni consists of a loaded flexible or jointed
band applied to the brake wheel employed in some forms of such lamps, and which
wheel is impelled to rotate in one direction by the descending weight of the so-called
carbon holder system or parts. According to this invention I arrange, apply, and
employ the said flexible band or brake, so that its primary duty is to retard the
slipping movement of the wheel when the tension of the band is relaxed, the final
or definite gripping action upon the brake wheel being performed by a supple-
mentary catch or pawl which mechanically prevents the wheel slipping in spite of
the retarding effect of the brake band until the said pawl is disengaged from the
wheel, even although the lamp should be subjected to considerable vibration as
is often the case in practice. For this purpose 1 provide the brake wheel with
ratchet teeth, in addition to the groove or plain part upon which the brake band
acts, and I attach to the said band at a convenient position a projecting part which
acts as a pawl when the band is pulled by the regulating core or armature a given
distance, as it then comes into contact with one or other of the ratchet teeth and
so locks the wheel until the said projecting part is disengaged from the ratchet
tooth or teeth by the opposite action of the regulating core or armature.
Instead of attaching a projecting part or pawl to the flexible brake band,
I sometimes attach the said lifting and stopping pawl to a separate lever working
on a convenient pivot, so that the said pawl engages the teeth provided on the
brake wheel and which actually rotates or locks it independently of the friction
produced by the flexible brake band.
According to the above arrangements the regulating coil must be of such a
strength or its action must be assisted by a spring or weight so that it can lift the
weight of the carbon holder system, and also overcome the spring or weight which
puts the tension upon the flexible brake band. Now, in order to avoid counter-
balancing weights or springs as much as possible and to regulate the lamp with as
little loss of energy in the regulating coil or coils as possible, I make the tension
weight counterbalance, or partly counterbalance the weight of the carbon holder
system in fact to raise it or tend to raise it so that the moving parts of the lamp
are in equilibrium, or nearly so, and therefore the effort of the regulating core
which acts upon the cord to lift and lower the said system may be small.
The release of the brake band in this case is effected by a lever actuated by the

page_text: regulating core, one end of which lever moves quicker than the weight, and when
the two come into contact the weight is very slightly lifted, thus relaxing the
tension of the cord upon the brake wheel and permitting it to slip.
The free end of the cord is attached to the reverse end of the above described
lever, but at a point nearer the axis of the lever than the point which releases the
weight. In combination with the above arrangement I also use the said pawl
previously described, so that the wheel cannot slip until the pawl is disengaged
from the ratchet teeth provided on the brake wheel.
I have described the application of the flexible band to the brake wheel used in
many are lamps, but according to this invention I apply it to the plain round rod
used in other well known forms of lamps called clutch lamps. In applying a
flexible band to control and retard the movements of the rod, I place around the
said rod a somewhat heavy metallic or loaded sleeve or collar through which the
rcd can freely pass; this sleeve is conveniently made hollow or chambered, the rod
fitting it loosely only at each end; through this sleeve at approximately right
angles to the rod I provide two apertures through which I pass a silk or other
flexible cord, taking the cord one or more turns around the rod; the two ends of
the cord being outside the heavy sleeve and led in an upward direction by suitable
grooves or idle pulleys provided on the sleeve, the ends of this said cord are
attached either directly to the regulating core or armature or a lever actuated by it.
Now it will be seen that if the loaded sleeve rests upon a fixed stop and the tension
of the cord is thereby relaxed, the rod is free to slip or fall through this said
sleeve, but if the regulating core or lever is raised, the cord is tightened around
the rod, so that eventually it so binds the rod that it is lifted along with the sleeve,
thus the carbons of an arc lamp may be separated and the arc established; now,
when the regulating core or its lever is lowered so that the heavy sleeve begins to
rest upon the fixed stop, the tension of the cord is so much relaxed that the rod
will begin to slip through the sleeve until it is again arrested by the increased
tension of the cord or band.
Instead of using a heavy sleeve a heavy or loaded lever working on a pivot may
be employed, through a slot in which the rod may pass, this is more convenient
when the round carbon holder rod is made taper.
Dated this 7th day of December 1894.
I, JAMES BROCKIE of 12 Tyson Road, Forest Hill, in the County of Kent,
Electrical Engineer, 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 :-
This invention relates to certain improvements in the brake mechanism of
electric are lamps when such mechanism consists of a loaded flexible or jointed
band applied to the brake wheel employed in some forms of such lamps and which
wheel is impelled to rotate in one direction by the descending weight of the so-
called carbon holder system or parts. According to this invention I
apply and employ the said flexible band or brake, so that its primary duty is to
arrange,
retard the slipping movement of the wheel when the tension of the band is relaxed,
the final or definite gripping action upon the brake wheel being performed by a
supplementary catch or pawl which mechanically prevents the wheel slipping in
spite of the retarding effect of the brake band until the said pawl is disengaged
from the wheel, even although the lamp should be subjected to considerable

page_text: vibration as is often the case in practice; for this purpose I provide the brake
wheel with ratchet teeth, in addition to the groove or plain part upon which the
brake band acts, and I attach to the said band at a convenient position a projecting
part which acts as a pawl when the band is pulled by the regulating core or
armature a given distance, as it then comes into contact with one or other of the
ratchet teeth and so locks the wheel until the said projecting part is disengaged
from the ratchet tooth or teeth by the opposite action of the regulating core or
armature.
Figure 1 of the accompanying drawings shows the above arrangement of the
brake band and pawl which is as follows-viz.-C is the flexible brake band, cord,
or chain connected through the medium of or by means of a pawl bar P, to a
spring S whereby a rigid connection is introduced between the end of the spring S
and one end of the band or chain, the end of this rigid connection being shaped
like a pawl to engage the teeth of the brake wheel B; the other end of the band C
is connected to the regulating core A or a link controlled by it, the band C passing
around the brake wheel B as shown. I prefer to enclose the spring S in a tube T,
pivotally suspended at one end as shown at T¹. A stop, say as W, prevents the
pawl P being dragged towards the centre of the wheel B and so locking itself, the
pawl P however is free to be pressed slightly outwards by the wheel as the latter
is rotated by the pawl P. The action of this arrangement is as follows:-
When no currents exists in the circuit of the lamp the core A descends and the
spring S is in consequence so relaxed that the wheel B is free to revolve, and the
carbons thus come together. When however the current is passing, the core A
pulls upwards and first tightens the band C on the wheel B with sufficient grip (on
the said wheel) as just to be able to turn it, and the pawl P is then very near the
ratchet teeth; now as the core A ascends, the wheel B is rotated by the pawl Pa
little, and the carbon points are thus separated and the arc struck. When the
resistance of the arc becomes too great the core A descends and the wheel B there-
fore turns slightly in a direction to cause the carbons to approach, and in time the
pawl P becomes disengaged from the teeth and the wheel is then only held or
controlled by the friction of the brake band C on the wheel B until the core A
descends far enough to so reduce the tension on the band C that the wheel B begins
to slip round slowly; if however this slip should be too much, the pawl P, by
the action of the core A, will again come into one of the teeth and prevent
further slip.
In this way the feed takes place from time to time, the pawl P being in readiness
to stop the wheel B should overslip take place say by excessive vibration of parts
or the too sudden movement of the regulating core.
Instead of attaching a projecting part or pawl to the flexible brake band, I some-
times attach the said lifting and stopping pawl to a separate lever working on a
convenient pivot, so that the said pawl engages the teeth provided on the brake
wheel and actually rotates or locks it independently of the friction produced by the
flexible brake band.
Figure 2 shows in elevation and Figure 3 in plan the above method of arranging
a brake band C and a safety pawl P pivoted on the loaded lever S. The brake
wheel B is provided as in the previous case with ratchet teeth in addition to the
groove or plain part upon which the flexible brake band Cacts; one end of this
brake band 1 fix to the loaded lever S the other end to a smaller lever L pivotted
to the lever S at S¹ the band C passing around the wheel B as shown, the safety
pawl P is conveniently pivotted to the loaded lever S as shown and is so arranged
that after the tension of the band C is put on by the regulating core A this pawl P
is quite near the teeth and ready to enter as in the case and manner previously
described. The smaller lever L is lifted at one end by the regulating core A in
order to tighten the band C on the wheel and is tripped by a stop E at the other
end to relax the pressure, the pawl P being tripped by the fixed stop E³ before the
lever L arrives upon its stop E.
According to the above arrangements the regulating coil must be of such a strength,

page_text: or its action must be assisted by a spring or weight so that it can lift the weight of
the carbon holder system, and also overcome the spring or weight which puts the
tension upon the flexible brake band. Now, in order to avoid the use of counter-
balancing weights or springs as much as possible, and to regulate the lamp with as
little loss of energy in the regulating coil or coils as possble I make the tension
weight counterbalance, or partly counterbalance the weight of the carbon holler
system, in fact to raise it or tend to raise it so that the moving parts of the lamp
are in equilibrium, or nearly so, and therefore the effort of the regulating core
which acts upon the cord to lift and lower the said system, may be small.
The release of the brake band in this case is effected by a lever actuated by the
regulating core, one end of which lever moves quicker than the weight, and when
the two come into contact the weight is very slightly lifted, thus relaxing the
tension of the cord upon the brake wheel and permitting it to slip.
The free end of the cord is attached to the reverse end of the above described
lever, but at a point nearer the axis of the lever than the point which releases the
weight. In combination with the above arrangement I also use the said pawl
previously described, so that the wheel cannot slip until the pawl is disengaged from
the ratchet teeth provided on the brake wheel.
Figure 4 shows the above described arrangement of levers. The weight S is
applied to one end of the brake band C as shown so that it tends to rotate the brake
wheel B in a direction to separate the carbons, the other end of the band C being
fixed to the lever L at a point F through the intervention of the pawl P and this
lever L is so pivotted at L' that the point G travels faster than the point F and
thus as the point G moves upwards it overtakes the weight S and in coming in
contact with it reduces the effective weight or pressure, and the grip of the band C
is therefore relaxed or reduced upon the brake wheel B permitting the latter to
slip the pawl P is as aforesaid interposed between the band C and the point F
in order to rotate the wheel B in a positive manner should the brake band C
permit the wheel B to overslip.
Although I have described my invention as applied to lamps with a single pair
of carbons yet the invention is equally applicable to lamps having more than one
pair of carbons.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In electric are lamps having a brake wheel or wheels, controlling the said
wheel or wheels by means of a band, chain, or wire, upon wilich tension is put by a
spring or weight, in combination with a pawl istantially as described and
illustrated with reference to Fig. 1 of the accompanying drawings.
2. In electric are lamps having a brake wheel or wheels, "ontrolling the same by
means of a loaded band in combination with lever- all sul tantially as described
and shown at Figs. 2 and 3 of the accompanying drawings.
3. In electric are lumps having brake wheels controlled I
lexible brake bands
or chains, the arrangement of the weights or springs attach i to the said bands so
as to turn or tend to turn the wheel in a direction to separat the carbons, and the
combination of levers, substantially as described and illustrated with reference to
Fig. 4 of the accompanying drawings.
4. The construction and arrangement of parts composing my improvements in
and relating to the brake mechanism of electric are lamps cc pbined and acting as
and for the purposes substantially as herein before described. ...
Dated this 5th day of October 1805
BREWER & SON,
London and Leeds, Agents for Applicant.