Improvements in Forced Draught Lamps.
Year: 1895

page_text: Date of Application, 17th Dec., 1895-Accepted, 23th Feb., 1896
COMPLETE SPECIFICATION.
Improvements in Forced Draught Lamps.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields, in the County of London
Gentleman, do hereby declare the nature of this invention (which has been
communicated to me from abroad by Robert Hitchcock, Manufacturer of
Watertown, Jefferson County, New York, United States of America) 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 what are known as mechanical or forced draught lamps
and has for its objects to strengthen the mechanism of such lamps, reduce the cost
of construction facilitate the separation and connecting of the parts for cleaning or
repairs, to obtain a uniform and efficient supply of air with smaller spring power,
to improve the brilliancy and steadiness of the light, to produce practically a silent
movement of the mechanism; to increase the duration of working with one
winding, and generally to improve the lamp in point of construction and operation.
The means by which the above objects are attained will be clearly understood
from the following description with reference to the accompanying drawings,
Figure 1 of which is a vertical section, partly in elevation, of a lamp constructed
in accordance with this invention.
Figure 2 is a side elevation, partly in section, of the air blast mechanism.
Figure 3 is an elevation and part section of the same at right angles to
Figure 2.
Figures 4 and 5 represent in elevation and vertical section respectively the cap
or dome detached.
Figure 6 is a plan of part of the drum which encloses the fan or blower.
Figures 7 and 8 represent in longitudinal section and plan respectively the step-
bearing of the spindle of the fan or blower.
Figures 9 and 10 are respectively an underside view and a vertical section of
the burner detached.
Figure 11 is a section of the burner socket drawn to a larger scale.
Figure 12 is a plan of the fan or blower detached and
Figures 13 and 14 are a face view and an edge view respectively of the worm
wheel (also drawn to a larger scale) for driving the fan or blower.
A represents the shell of the lamp, which may be of any suitable or convenient
shape, according to the use for which the lamp is designed. The lamp illustrated
in the drawings is designed for household purposes.
It is desirable to use with the lamp as wide a wick as possible, and in order to
employ a broader wick than usual without increasing the size of the dome B
usually employed, the said dome is according to this invention provided with
hollow extensions or recesses b at the ends of the wick-slot, which slot is made to
extend into the said hollow extensions or recesses.
The dome B is provided on the exterior with projections or spurs (Figures 4
and 5) which projections are preferably formed by pressing them out of the side
of the dome. Over these projections the ring of an ordinary lamp shade
support may be sprung, the said projections preventing the shade from slipping off.
Heretofore the dome, when detachable from the burner has been simply pushed
into place, reliance being had upon a close fit to retain it in position. According
Pin1

page_text: to this invention the dome B is provided with means for securely connecting it to
the shell of the lamp the said means consisting of spring catches , having hooked
ends which when the dome is in place catch under an annular shoulder a inside
the shell of the lamp, with which shoulder the hooked ends of the catches
automatically engage when placing the dome in position. For each of the
catches there is provided a push pin ³ extending through the side of the dome,
so that by pressing these push pins inwards the catches 62 can be forced out of
engagement with the shoulder a and so permit of the removal of the dome. The
detachable dome must be so placed in position that its slot is in alignment with the
flat-wick tube, and as the position of the wick tube is variable with different
burners, (according to the way the screw threads are cut) the dome should not
have a fixed or definite position. It will be seen that the construction of the
engaging catches 6 is such that they will operate in whatever position the dome
may be placed.
In lamps as heretofore constructed the burner C, which carries the flat-wick
tube C, is provided with a bottom plate to which the lower end of the said tube.
is attached, the wick operating wheels c being therefore enclosed and inaccessible
for adjustment, or for removal of threads, from the wick, which may become
entangled in them. According to this invention the said bottom plate is
dispensed with thereby leaving the space within the support entirely open and the
wick operating wheels accessible. A ring c¹ (Figures 9 and 10) is fixed around
the interior of the bottom of the burner, and notches are provided at diametrically
opposite points in this ring into which notches the edges of the flat wick tube are
fixed.
Heretofore, in screwing the burner of a lamp into its socket difficulty has been
found in making the thread on the burner engage properly with the screw thread
in the socket C and the screw threads frequently become damaged and rendered
useless. To obviate this defect the socket of a lamp constructed according to this
invention is provided with an annular unthreaded flange c (Figure 11) above the
threaded portion of the socket, which flange constitutes a recess or seat of
uniform depth so that the burner can be set squarely in this seat, and turned until
its thread engages the thread in the socket. This construction facilitates the
replacement of the buruer when removed for filling the reservoir, or for other
purposes.
Mechanical lamps as heretofore constructed have generally been provided with
blowers or fans having inclined blades or vanes, constructed on the principle of
the screw propeller, taking in a current of air from beneath, and delivering it
from the top face of the wheel. Owing to the reaction or back-pressure, and the
peculiar operation of these blowers, considerable slip takes place, requiring the
use of a comparatively large wheel, consequently necessitating the use of a strong
spring to drive it.
According to this invention the blades or vanes e of the fan or blower are
arranged with their acting faces parallel to the axis or spindle of the fan. The
said fan or blower is covered by a drum E which is closed at the top, but is
provided in its periphery with outlet openings e¹ for the air. In fan-blowers
which have a single exit, tangential to the periphery of the casing, there is a
regular pulsation in the current of the air, which, in a lamp, is very objectionable.
It is one of the objects of this invention to produce in the air-chamber of the oil
reservoir, a steady and uniform pressure of air, and to thorougly diffuse the air in
the said chamber. This result is attained in part by forming several openings in
the periphery of the drum E sufficient of the periphery being left to cut off the
space within the drum, from the pressure of the air in the surrounding space or
air chamber.
Preferably the openings for the passage of air from the interior of the drum
have each an oblique edge e³, so that the acting area of the blades, as they pass
these openings are gradually cut off or reduced and so prevents pulsations.
By these means pressure is maintained in the air chamber above the diaphragm F,

page_text: and in the space leading to the burner, this pressure being distinguished, and
different in its effects, from a mere current of air, as produced by the air blast
mechanism heretofore employed.
In the neck or contracted part of the shell A of the lamp is a ring or thimble G
which serves, as heretofore, to arrest oil-drippings and bits of wick. According
to this invention this ring or thimble is provided with a flaring mouth through
which the air passes, and in this flaring mouth, are vertical corrugations 9 the
effect of which is to conduct the air in a vertical direction or to straighten the
air currents, when they have been forced in a spiral or oblique direction. This
device in connection with the blower or fan described and shown, has been found
to be very effective for the purpose described. The vertical corrugations may be
provided at any convenient part of the air-passage where they will act effectively
on the air-currents, but it has been found most convenient to provide them on the
ring or thimble as shewn.
The vanes of the blower or fan are carried on arms projecting from a boss or
web in which are perforations (Figure 12) constituting passages for air to the
space above the said boss or web to inside the vanes e.
The drum E rests upon a diaphragm plate F, which fits in an opening of
corresponding shape in a diaphragm F, the said diaphragm plates when fitted
together constituting a continuous horizontal partition across the shell of the lamp,
the only passage for air to the space above this partition being through an opening.
in the centre of the plate F' (Figure 2) through which opening the air is drawn by
the blower or fan. To insure a tight fit, between the diaphragm plates F and F a
collar fis provided around the opening in the plate F in which the plate F* fits.
The space above this partition constitutes a compressed air chamber, containing
the blower, and is a valuable feature of the invention as it conduces greatly to the
steadiness and brilliancy of the flame. Heretofore in lamps of this description the
blower or fan has been situated directly in, or in close proximity to, the neck or
contracted portion of the shell of the lamp.
The diaphragm plate F is provided on its upper side with an annular rim F
within which closely fits a horizontal flange et formed on the lower end of the
drum E (Figure 2) the drum being thereby accurately centered. This feature is
of special importance as the drum contains the upper bearing of the spindle / on
which the blower or fan is mounted, and the centering of the drum insures the
proper adjustment of the worm on the said spindle with reference to the gearing
of the spring motor, it also admits of the ready removal and accurately replacing
of the drum and also of the fan and its spindle.
This construction, moreover dispenses with the necessity of the jewel heretofore
employed for the upper end bearing of the spindle h. In the .construction shown.
the drum has a raised boss e (Figure 6) which is perforated to form a bearing for
the upper end of the spindle h, which perforation is covered by a spring arm or
plate i pivotted at it and normally held in place by a catch pin Figures 3 and 6.
so that it can be turned aside for the purpose of oiling the bearing.
The spring
arm or plate covers the perforation in the raised boss thereby protecting the
bearing, and also preventing the spindle h from slipping out of place, when the lamp.
is tilted in handling or in transportation.
With lamps of this description as hitherto constructed annoyance has been
occasioned by the jewel forming the lower or step-bearing of the fan spindle, falling
out of place and being lost, when the mechanism is taken to pieces. To prevent this
annoyance the jewel k is according to this invention held in a support formed by a
clamp spring (Figs. 7 and 8) bent upon itself to clamp the jewel between its two
members the lower member of the clamp being slightly recessed as shewn to receive
the jewel. The upper member of the clamp has a hole therein through which the
lower end of the spindle h can pass and rest upon the jewel k. This support is
preferably pivotted at its end to an arm or bracket so that it can be swung
aside. The arm or bracket is forked or notched at its end into which the
spring-support ¹ snaps when swung into place,

page_text: Heretofore the worm on the fan spindle k has been driven by a rubber worm-
wheel having slender exposed teeth on its periphery. On account of the brittleness
of hard rubber and the exposure of the teeth frequent breakage of the teeth
occurs.
One of the prominent objects of this invention is to produce a lamp which is not
likely to be injured under ordinary conditions and which can be readily taken to
pieces and reconnected by persons without mechanical skill, and without the use of
tools. To overcome the liability to breakage of the rubber worm-wheel m it is
constructed according to this invention in the form of a crown wheel (Figs. 3, 13
and 14) or it may be a bevel wheel, that is to say with teeth radially disposed on
the face instead of on the periphery. The acting sides m' of these teeth are nearly
perpendicular to the face of the wheel. By this construction a comparatively long
contact is ensured between the worm and each tooth of the wheel thereby obtaining
gain of power in driving the worm whilst the diameter of the worm-wheel is
reduced. These advantages are all of importance, but the most important effect
gained by this construction is the silent movement, the clicking noise heretofore
produced by the impact of the successive teeth of the wheel upon the worm, being
entirely eliminated.
Heretofore, a main-spring barrel with an internal gear, forming part thereof has
been combined with the train of gearing in such manner as to secure a gain in
compactness, reduction of size, number and weight of parts, the barrel being carried
on a vertical arbor and enclosed in a cylindrical jacket, and in order to gain further
advantages without sacrificing those mentioned the main-spring barrel N according
to the arrangement shewn is mounted on a horizontal arbor n and is situated outside
the supporting plates 00' of the frame, the arbor being extended so as to pass
through both plates.
On the end of the arbor n furthest from the barrel is a ratchet-wheel n¹ which is
slipped on to the squared end of the arbor, and held in place by a wing-screw n².
The barrel is by this arrangement easily accessible, and being entirely clear of the
frame and train of gearing, its size can be increased or diminished without altering
the internal gear P which it carries or any of the other parts. Variations of size
of the main spring are desirable, according to the particular use to be made of the
lamp. Furthermore, to remove the barrel and its arbor, it is only necessary to
unscrew the wing-screw n' which can be done with the fingers.
The pawl or click q which gears with the ratchet n¹ is pivoted on the back-
plate O¹ and is provided with a spring q'. The position of the barrel on the outside
of one plate and the pawl and ratchet outside the other plate is of special
convenience for letting out the power of the spring, in doing which it is
necessary to exercise great care in order to unwind the spring gradually. By
the construction shown this can be done by holding the barrel with one hand, and
with the other manipulate the pawl throwing it into and out of engagement with
the ratchet as required.
'
When the pawl is out of engagement with the ratchet, the spring q¹ presses on the
end of the pawl, and holds it in that position, the movement of the pawl away from
the ratchet being limited by a stop pin q2 (Fig. 1).
As before mentioned, the entire mechanism is constructed with a special view to
its parts being quickly taken apart and connected together accurately by persons
not possessing special mechanical skill and without the use of tools. As these lamps
are often sent to places remote from cities, the advantage of these provisions will
be readily appreciated. Some of the features of construction adopted with this end
in view have already been described, but others have yet to be indicated.
The front plate O of the frame is fixed to the diaphragm plate F*,
herein before referred to, by the pillar - and studs and by a lug on
the plate F rivetted to the plate O. The support of the lower bearing k
of fan spindle is also permanently attached to the plate O. Since the
drum E, which contains the upper bearing of the fan spindle centres itself in the
recessed diaphragm plate F as already explained, and is fastened thereto by thumb

page_text: screws (and no tools are required) no skill is necessary in adjusting and con-
necting these parts. Furthermore, the back plate O' is detachably secured to the
pillars(which are permanently attached to the front plate) by means of
screws shaving wings (Fig. 3) instead of an ordinary nick, so that they can be
manipulated by the fingers. Upon removing these screws the plate O and the
train of gearing, the arbors of which have bearings in the two plates O O¹, can
be detached for cleaning or other purposes. It will be observed that the detach-
ment of the removable back plate O' does not involve any change in the adjustment
of the bearings of the fan spindle.
The plates O O' are attached to a bottom plate T, which is attached to ears T
on the shell by means of screws (Fig. 1). These screws have the ordinary nick t
for engagement of a screw driver, and also a milled head t2 permanently fastened
thereto, for turning by hand.
The internal gear P in the barrel N engages a pinion p (Fig. 3) the arbor of
which pinion has one bearing in the plate O₁ and the other in a bracket pl
attached to plate O.
In operation the air enters by holes a' in the base of the shell into the chamber
beneath the diaphragm F. Thence it is drawn by the fan into the drum E through
the opening (Fig. 2) in the diaphragm plate F2. The fan delivers the air through
the side openings in the drum E into the air-chamber above the diaphragm F and
beneath the oil-reservoir H. In this chamber as well as in the annular space
between the shell and the reservoir and in the dome around the burner, the air is
in a state of compression, the pressure upon the flame being practically steady and
uniform and is not subject to puffs or gusts, or wavering currents of air, the
resulting light being steady and brilliant.
Obviously the details of construction may be much modified, and some of the
described improvements may be omitted without departing from the spirit of
the invention.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In a forced draught lamp, the combination with the burner, and means for
supplying currents of air to the burner of a dome provided with a wick-slot, and
having extensions at the end of the said slot into which the slot extends substantially
as herein before described.
2. The combination with the shell of a mechanical lamp, the oil reservoir, and
the burner having a screw connection with the said reservoir, of a detachable
dome, provided with internal spring-catches for locking it to the shell, the said dome
being adjustable axially, and means for disengaging the said catches to permit
removal of the dome, substantially as herein before described.
3. The combination with the burner comprising a shell with an open bottom, and
a ring reinforcing the lower edge of the said shell, and notched at diametrical
opposite sides, of a flat wick-tube fixed in the said notches, a wick-spindle, and
wick-wheels inside the said shell, substantially as herein before described.
4. In a forced draught lamp, the arrangement of a pressure chamber, formed by
the lamp-shell and a diaphragm extending across the same, the fan or blower being
located in the said chamber and covered by a drum having lateral openings therein
whereby air is compressed in said chamber, and supplied in a steady current to the
flame, substantially as herein before described.
5. The combination with the shell having a contracted portion or neck, of a
diaphragm extending across the said shell beneath the neck and forming an air
chamber, a fan or blower, and spring-motor mechanism for operating the same, the
frame of the said mechanism being provided with a top-plate which fits, and closes
an opening in the said diaphragm, so that the blower is supported in the said
chamber, and a drum separating the said fan or blower from the said air chamber
and provided with air-passages, substantially as hereinbefore described.

page_text: 6. The combination with the shell and burner of a mechanical lamp, of a fan or
blower, consisting of blades or vanes whose sides are parallel to the vertical axis
of the fan or blower, a drum having a solid top covering the said fan or blower and
outlet openings through the peripheral band, and operating mechanism for driving
the said fan or blower, substantially as hereinbefore described.
7. In a mechanical lamp, the combination with the shell having a contracted
neck, and a diaphragm extending across the shell beneath the said neck and having
a single opening, of a removeable clock-work mechanism, comprising side frames
and a top-plate the top plate fitting the opening in the said diaphragm, and a
spring and driving gears, a fan or blower above, the said top-plate driven by the
said spring and gears, and a drum seated upon the said top-plate and having outlet
openings, substantially as herein before described.
8. In a mechanical lamp, the combination with the shell having a contracted
neck, of a ring or thimble set in the said neck and projecting upwardly therefrom,
the said ring or thimble being provided with a flaring mouth, and air-forcing
mechanism in the shell beneath the said thimble, substantially as hereinbefore
described.
9. In a mechanical lamp, the combination with the fan or blower, its spindle, and
its actuating mechanism of a recessed plate forming part of the framework of the
said mechanism, and an enclosing drum for the said fan or blower having one of
the bearings of its spindle, and provided with a flange fitting the recess in the said
plate so that the drum is self-centering, substantially as hereinbefore described.
10. The combination with the framework and with the fan or blower and its
vertical spindle, of a step-bearing for the lower end of the said spindle, comprising
a jewel and a support formed by a metal strip, recessed to receive the said jewel and
bent upon itself to clamp the latter between the two ends of the strip, the said
strip being pivotally attached to the said frame-work substantially as hereinbefore
described.
°
11. In an air-blast mechanism for forced draught lamps, the combination with
the fan or blower, its spindle and a worm on the said spindle, of a worm wheel
formed of sound deadening material having radially arranged teeth on its face
engaging the said worm, and mechanism for continuously rotating the said wheel,
substantially as herein before described.
12. In an air-blast mechanism for mechanical lamps the combination with the
frame-work comprising upright side-plates in which the arbors of the clock-work
train of wheels are journaled, of the main-spring, its barrel provided with an
internal gear, the said barrel being outside one of the said plates, and a horizontal
arbor for the said main-spring extending through both of the said plates the said
spring and barrel being detachable, substantially as herein before described.
13. The combination with the upright side plates and means for detachably
fastening the same together, of a main-spring barrel outside one of the said plates,
an arbor therefor extending through both of the said plates and having a squared
end, and a ratchet wheel detachably secured to the squared end of the said arbor,
substantially as herein before described.
14. The combination and arrangement of parts constituting the improved
forced draught lamp hereinbefore described and illustrated by the accompanying
drawings.
D11: 171 T
e
1
1008
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.