Improved Methods of and Apparatus for Heating Metal Articles by Electricity.
Year: 1891

page_text: Date of Application, 29th Dec., 1891-Accepted, 23rd Apr., 1892
COMPLETE SPECIFICATION.
Improved Methods of and Apparatus for Heating Metal Articles
by Electricity.
I, EDWIN ELLIOTT ANGELL, of Somerville, in the County of Middlesex
and State of Massachusetts, United States of America, Machinist, do hereby
declare the nature of my 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 the art of and apparatus for heating metals by
electricity, and is especially adapted for heating mandrels, milling cutters, taps,
reamers, twist drills, arbors, bushings, thin cutters, and similar metal working and
other tools and articles preparatory to hardening and tempering them.
The objects of this invention are to provide a method and apparatus in which
the advantages of the electric current as a heating agent for metals may be utilized
economically, and an apparatus in which the mechanism may be adjusted with
facility for the proper heating of any given tool of the class above indicated, and
then utilized for the uniform heating to the same degree of temperature of any
number of like tools.
Figure 1 of the accompanying drawings represents a side elevation of this
improved electric heater.
Figure 2 represents a plan view thereof.
Figure 3 represents an end elevation thereof.
Figure 4 represents a side elevation, partly in section of a pair of electrode
spindles adapted for use in this apparatus for heating thin pieces or disks
of metal.
Figure 5 represents a side elevation partly in section of a pair of electrode-
spindles for use in this apparatus of a construction adapted for heating arbors,
reamers, bushings and similar articles.
Figure 6 represents one form of stationary electrodes which may constitute an
equivalent of the form of stationary electrodes shown in Figures 1, 2 and 3.
Figure 7 represents details of the bolder for the stationary electrodes shown in
the first three figures.
Figure 8 represents details of the electrode spindles.
Figure 9 represents the character of tools this apparatus is especially adapted to
heat for the purpose of hardening and tempering.
Figure 10 is a diagram showing the apparatus in circuit.
Figure 11 represents a plan of the central portion of the apparatus including
means for equalizing the traverse of the currents conducted to opposite ends of
the work.
Figure 12 represents an end view of the parts shown in Figure 11.
Figure 13 represents in detail the arm for holding stationary one of the
conductive collars of one of the electrode spindles and the bracket for supporting
said arm.
Similar numerals of reference indicate corresponding parts in the different
figures.
The frame 20 supports an elevated bed 21, which is provided with a central
longitudinal guideway 22 and two longitudinal dovetail grooves 23 and 24 near the
front and rear sides respectively. A gib or strip 25 is secured in said guideway
by means of lateral screws 26, and the width of the guideway is adjusted by these
means.
A sliding carriage 30 adapted to reciprocate on said bed is provided on its under
side with a longitudinal dovetail rib 31, which engages the dovetail guideway 22 of

page_text: the bed and on its upper face with a longitudinal dovetail groove 32. The dovetail
rib of the carriage is provided on its under side with a longitudinal rack 33. A
transverse shaft 34 is journaled in the frame and in a lateral sleeve 35 projecting
therefrom. A pinion 36 is disposed on said shaft within the frame and a crank 37
is disposed on said shaft outside the frame. A short transverse shaft 38 is also
journaled in the frame above the shaft 34, and a gear 39 thereon meshes with the
pinion 36 and with the rack 33, whereby motion is communicated from the crank
to the rack, and the carriage is thereby reciprocated.
These
Two similar end standards 40 and 41 having elongated feet 42 are adjustably
secured on the carriage 30 by means of clamping screws 43 which extend through
said feet into the dovetail groove 32 and take into nuts 44 disposed therein.
standards are provided at their upper ends with horizontal sleeves 45 and 46 in
alignment with each other longitudinally of the machine. These sleeves are
provided with insulating bushings 47 having flanges 48 at their inner ends.
Steel sleeves or linings 49 are disposed in the insulating bushings to prevent wear
thereof.
Two similar electrode spindles 50 and 51 are supported in alignment with and
apart from each other in the sleeves 45 and 46, being insulated therefrom by the
bushings 47, which are protected by the steel linings 49. These spindles support
and center the work, pass currents into or out of the ends thereof and are movable
for shifting the work with relation to the stationary electrodes hereinafter described
for taking out or passing in currents at different points at the sides of the work,
The inner ends of these spindles are provided with clamping heads 52, between
which the article of metal to be heated is supported. These clamping heads are
preferably provided with contact faces 53 composed of platinum or other suitable
electrically conductive material. The outer portions of the spindles which slide in
the insulated sleeves are shown of smaller diameter than the inner portions which
project toward each other inside the inner ends of the sleeves. Spiral springs 54
are disposed around said spindles between shoulders 55 thereon and the flanged
ends 48 of the insulating bushings. The springs allow the spindles to yield under
the expansion of the article being heated, and they also permit the spindles to
yield to receive the article to be heated and cause them to close against said article
to clamp it, whereby adjustment of the standards for every insertion and removal
of articles of the same length is avoided.
Adjustable collars 60 and 61 are disposed on the spindles, being held fast thereon
by means of the set screws 62. These collars are composed of electrically
conductive material and are provided with binding posts 63 and 64 for clamping the
electric conductors.
The clamping heads 52 of the spindles are of different forms for holding different
articles, those shown in Figure 1, 2 and 8 being in the form of cones 52 for
engaging solid cylindrical articles, those shown in Figure 4 being in the form of
flat disks 52', and their contact faces in the form of rings 53' for engaging thin
cutters and the like; and those shown in Figure 5 being funnel-shaped or flaring,
as shown at 52", to receive arbors and other articles to which they may be
adapted.
A side standard 70 is adjustable longitudinally of the bed in the groove 23 at
the front side thereof, and a similar side standard 71 is likewise adjustable in the
groove 24 at the rear side of the bed. These standards are disposed opposite each
other on opposite sides of the article or work held between the electrode spindles
of the side standards, and serve as supports for the holder of the stationary
electrodes. They are provided with feet 72 through which set-screws 73 pass and
take into nuts 74 in the longitudinal grooves 23 and 24 of the bed 20. They are
also provided at their upper ends with flanged rests 75. The rear standard 71 has
a stop arm 76.
The electrode holder for the stationary electrode supported by these side
standards 70 and 71 is a ring-shaped device composed of two semi-circular
sections 80 and 81. These sections are provided with lugs 82 and 83 at their
1

page_text: opposite ends which project into the rests 75 of the standards 70 and 71. The
rear ends of the ring sections are hinged to the rest of the rear standards by means
of the screw pintle 84. The front ends of said sections are locked in closed
position in the rest of the front standard by means of a hinged locking latch 85
pivoted therein at its lower end, and screw-threaded and provided with a
clamping screw 86 at its upper end. The semi-circular sections 80 and 81 are
provided with radial recesses 87, see Figure 7, and with hinged clamping plates 88
having corresponding recesses on their inner faces. These recesses are provided
with insulating bushings 881, Figure 7, and when the clamping plates are closed,
form radial slots through which stationary electrodes 90 project into contact
with the sides of the article to be heated. The outer ends of the hinged clamping
plates 88 are provided with set screws 89, which take into screw-threaded holes
in the face of the ring sections, whereby the hinged clamping plates may be closed
tightly against the electrodes 90 to clamp them in position.
A cable 100 connected with the positive pole of a dynatno or other suitable source
of electricity, is provided with branches 101, and 102, and these branches are
connected respectively with the binding posts 63 and 64 of the collars 60 and 61
A cable 110 con-
on the electrode spindles 50 and 51 which support the work.
nected with the negative pole of the same source of electricity, is provided with
branches 111, 112, 113, and 114, which are severally connected with the stationary
electrodes 90 supported in the ring-shaped holder 80 and 81 surrounding the work,
and upheld by the side standards 70 and 71. The polarity of the cables may be
reversed, and alternating currents may be employed.
In the use of the apparatus having stationary electrodes, as shown in the first.
three figures, the upper section 81 of the ring-shaped electrode support is swung
back into contact with the stop 76 on the side of the rear standard 71, and a
milling cutter, as 200, or other device to be heated, is placed end wise between the
electrode spindles 50 and 51, said spindle yielding slightly under the action of the
springs 54 to permit the adjustment of the article to be heated. The upper
section of the ring-shaped holder is then closed and locked by the locking device
herein before described. The electrodes 90 are then adjusted so that their ends
come in contact with the sides of the article to be heated, and clamped in position
The electric currents are then
by means of the hinged clamping plates 88.
switched on and enter the ends of the article through the supporting electrode
spindles 50 and 51, and pass out laterally or radially through the sides of the
In order to heat the article
article by means of the stationary electrodes 90.
uniformly throughout its length, the operator turns the crank 37 alternately in
opposite directions whereby the carriage 30 carrying said electrode spindles is
reciprocated, causing the work to be moved back and forth, and the points of
lateral contact of the stationary electrodes to be shifted longitudinally along the
work. The direction of the currents may be reversed or shifted; preferably
alternating currents are employed.
To avoid short-circuiting of the entire current through either of the branches
of the positive cable 100 during the reciprocation of the carriage and the electrode
spindles, means are provided for equalizing the distance through which the currents
passing through the branches 101 and 102 travel. The means herein shown for
this purpose consist of mechanism for holding the rings 60 and 61 stationary,
while the electrode spindles slide back and forth through them during the recipro-
cation of the carriage. For this purpose a screw-rod 120 is supported horizontally
of the machine in the standard 70 being clamped therein by a set-screw 121. Two
brackets 130 and 131 provided with forked ends 132 are disposed on the screw-
rod 120 opposite the electrode spindles 50 and 51 respectively. Adjusting nuts 133
are disposed on the screw-rod between the forks of the brackets and serve to adjust
said brackets on said rod. Arms 140 and 141 are fastened at their lower ends to
the brackets 130 and 131, being insulated therefrom. These arms are provided
with semi-circular forked ends 142 which engage the binding posts of the collars 60
and 61 and hold the latter stationary during the reciprocations of the electrode

page_text: spindles, whereby an equal distance is maintained between each branch of the
positive cable and the negative electrode.
The electrodes 90 for some kinds of work are preferably provided at their
contact ends with antifriction rollers of copper, platinum, or other suitable
material, as illustrated in Figure 6.
In some cases the electrodes 90 may be dispensed with and the opposite electrode
spindles 50 and 51 connected with opposite poles of the dynamo, as shown in
Figures 4 and 5.
In Figure 4 a disk-shaped cutter 210 is interposed between the ring-shaped faces
of the flat-headed electrode spindles.
In Figure 5 a cutter or other article 220, having a central aperture, is disposed
on the arbor 230, which is supported endwise between the flaring-headed spindles.
In this case the heating point is developed midway between the electrode spindles
at the point 221, and the cutter or article 220 may be shifted on the arbor 230 as
indicated by dotted lines, in order to distribute the heat uniformly throughout the
cutter for the purpose of drawing the temper therein.
Rheostats may be used for regulating the currents.
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 an electric heater, the combination of two electrodes disposed in position
for contact with opposite ends of the article to be heated, and an electrode or
electrodes disposed in position for contact with the sides of said article.
2. In an electric heater, the combination of two electrode spindles disposed in
alignment and adapted to support the work, and an electrode or electrodes disposed
in position for contact with the work at points between the contact of the electrode
spindles.
3. In an electric heater, the combination of stationary electrodes, a bed, a sliding
carriage thereon, electrode spindles supported on said carriage, and means for
reciprocating said carriage between the stationary electrodes.
4. In an electric heater, the combination of a bed, standards disposed at opposite
sides of said bed, an electrode holder supported on said standards, a stationary
electrode or electrodes disposed in said holder, a sliding carriage on said bed,
standards on said carriage provided with insulated sleeves, electrode spindles
disposed in said sleeves in alignment with each other for supporting the work, and
means for reciprocating said carriage between the stationary electrodes.
5. In an electric heater, the combination of two standards provided with insulated
sleeves, two electrode spindles disposed in alignment, and having their bearings in
said sleeves, and springs for permitting the spindles to yield.
6. In an electric heater, the combination of a bed, standards disposed at opposite
sides thereof, and longitudinally adjustable thereon, an electrode holder supported
on said standards, electrodes disposed in said holder, a sliding carriage on said bed,
end standards adjustable longitudinally on said carriage, electrode spindles supported
on said standards, and means for reciprocating the carriage.
7. In an electric heater, an electrode holder consisting of a ring provided with
insulated radial slots for containing the electrodes.
8. In an electric heater, an electrode holder consisting of a ring composed of two
sections hinged together, and provided with radial insulated slots for containing the
electrodes.
9. In an electric heater, an electrode holder consisting of a ring provided with
radial recesses, and with hinged clamping plates having corresponding radial
recesses, said recesses forming insulated radial slots for containing the electrodes.
10. In an electric heater, the combination of two end standards provided with
sleeves, flanged bushings disposed in said sleeves, and electrode spindles, the outer
portion of which are of reduced diameters adapted to fit within the bushed sleeves,

page_text: springs interposed between the flanges of the bushings, and the shoulders of the
spindles.
11. In an electric heater, the combination of two standarls or supports provided
with insulated sleeves, two electrode spindles disposed in said sleeves, and adjustable
collars on said sleeves provided with binding posts.
12. In an electric heater, the combination of two electrode spindles provided with
flaring heads, and supports for said spindles.
13. The method of heating an article by electricity, which consists in subjecting
the article to the action of electric currents entering in opposite directions at the
ends of the article, and passing out at the sides thereof.
14. The method of heating an article by electricity which consists in subjecting
the article to the action of electric currents entering in opposite directions at the
ends of the article and passing out at the sides thereof, the lateral meeting or
impinging point of the currents being shifted longitudinally of the article during
the passage thereof.
15. The method of heating an article by electricity which consists in subjecting
it to the action of electric currents traversing the article in lines passing through
the ends thereof and meeting or impinging at the sides thereof, the lateral meeting
or impinging point or points of the currents being shifted longitudinally of the article
during their passage therethrough.
16. In an electric heater, the combination of two electrode spindles for contact
with the work to be heated, an electrode or electrodes disposed in position for con-
tact with the work at points between the contact of the electrode spindles, means
for reciprocating the electrode spindles and the work, and means for equalizing the
two currents of the electrode spindles in the manner described.
17. In an electric heater, the combination of stationary electrodes, a bed, a sliding
carriage thereon, electrode spindles supported on said carriage, conductive contact
pieces or rings on said spindles, cable connections therefor, and arms engaging
said contact pieces for holding them stationary during the reciprocation of the
spindles.
18. In an electric heater, the combination of stationary electrodes, a bed, a
sliding carriage thereon, electrode spindles supported on said carriage conductive
contact pieces or rings on said spindles, cable connections therefor, means for
reciprocating said carriage between the stationary electrodes, a screw-rod supported
parallel with said electrode spindles, brackets disposed on said rod opposite said
spindles, arms attached to said brackets and engaging said contact pieces, and
adjusting nuts on said rod for adjusting said brackets and arms.
Dated this 18th day of September 1891.
EDWIN ELLIOTT ANGELL.
Witnesses:
F. C. SOMES, Lawyer,
514, F. Street, N.W., Washington, D.C., U.S.A.
EDWARD NEWITT, Machinist,
Fitchburg, Mass.