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Патент USA US2411439

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Nov. 19, 1946.
Filed June 9, 1944
In Him
Patented Nov. 19, 1946
George Herbert Lee, Bristol, England, assignor
to The Bristol Aeroplane Company Limited,
Bristol, England, a British company
Application June 9, 1944, Serial No. 539,577
In Great Britain April 6, 1943
1 Claim.
(Cl. 113-112)
This invention concerns improvements in or
relating to brazing, soldering or the like proc
According to the present invention a brazing,
soldering or the like process is characterised in
that the parts to be united by the process are r0
chine the ?ns with special care to provide for
their varying edge shape as would be required if
intimate contact between the ?ns l‘! and the face
l5 was required: this simpli?es the production
of the ?ns and their assembly on the base.
The upper edges of the ?ns H are secured to a
tated together whilst the brazing, soldering, or
tray is which lies transversely of the ?ns. The
the like material is in a molten condition whereby
tray has a central opening l9 to permit spark
said material is caused to now over said parts by
plugs to be passed down into the head and
centrifugal action.
10 screwed into the spark~plug adaptors 29 which
According to another feature of the present
are carried in the plate Hi. The adaptors are
invention the process is characterised in that the
screwed into the plate and then brazed in. The
parts to be united by the process are rotated to
?ns ll extend parallel to each other and chord
gether at a varying speed whilst the brazing,
wise across the sleeve. To enable the spark plugs
soldering or the like material is in a molten con
to pass downwardly to the adaptors 2E], those ?ns
dition whereby said material is caused to ebb and
which would otherwise extend across the spark
?ow over said parts.
The invention has particular application to the
plug holes are terminated at the edge thereof.
There is thus formed a tunnel through which the
production of the base of a junk-head of a sleeve~
plugs pass when being ?tted to the head.
valve internal combustion engine. Accordingly 20 The base i i is received by the steel sleeve l2, a
in order that the invention may be clearly under
spigot joint 25 being provided by extending the
stood, the production of such a junk-head will
now be described, merely by way of example, with
reference to the accompanying drawing where
Figure 1 is a side elevation of a junk-head
which has been produced by a process in accord
ance with the invention, the head being shown
partly in section, and
Figure 2 is a perspective view of an apparatus
for carrying out said process.
inclined wall of the face i5 upwardly within the
sleeve. The base i l is brazed to the sleeve at the
spigot joint 2|.
The ?ns ll‘ are brazed to the face Hi, the
adaptors Zll into the base H, and the latter to
the sleeve l2 by a single brazing operation. In
preparation for this operation the following
treatments are carried out on the separate parts:
1. The adaptors 2% are coated with a flux and
are then screwed into the plate M. The face l5
of the base is brushed with a solution of the flux
in water and ?nally a similar treatment is ap
Referring to Figure 1, the junk-head H) is of
two-piece construction-one part thereof is a
plied to the face of the spigot joint 2| for the
base I l and the other part is a steel sleeve l2 to
which the base I! is attached and which is itself
secured to the cylinder by studs passing through
2. The steel sleeve 22 is coated with a brazing
the ?ange I3.
material by dipping the sleeve into a bath, the
outside surface being protected by a heat resist
The base [I comprises a plate l4, one face 15 of
ant cement. To ensure adhesion of the brazing
which is dish-shaped with a generally ?at cen
tral portion [6, and a plurality of ?ns l'l secured Lil) material, the inside and lower edge of the sleeve
by brazing to the .face l5 and the inner surface
ii.’ is brushed with ?ux. The sleeve is dipped
in the bath of molten brazing material to a depth
of sleeve [2. The ?ns ll are approximately of a
corresponding con?guration to the face 15 to
greater than the height of the ?ns on assembly.
which they are attached.
When the sleeve has attained the temperature
The ?ns, which are pre-iormed, are made to
of the bath and the coating is complete it is re
be a loose fit with the inclined wall of face I5
moved and allowed to cool. The excess brazing
and the brazed joint is of such a depth that com
material is removed from the sleeve so that
plete contact between the lower edge of the ?n
?nally a thin continuous coat is left on the inner
surface and lower edge of the sleeve.
and the inclined wall is ensured. Whilst the
?ns can be readily machined to be in more inti
3. The edges of the ?ns H (which ?ns are at
mate contact with the ?at central portion than
tached to the tray !8 so as to form a pack) are
with the inclined wall it is desirable that this
not previously coated with flux in preparation
brazed joint should also be of a considerable
for the brazing operation.
depth to ensure complete contact. By providing
this form of brazed joint it is unnecessary to ma—
The base plate M, sleeve 52, and the pack of
fins are then assembled. The pack of ?ns is
?rst placed upon the face I5 of the plate l4
(ensuring that the ?ns are properly positioned
relative to the plug adaptors) and then the steel
sleeve I2 is spigoted on to the plate I 4. A re
taining band 42 is then placed in position on 5
the outer cylindrical surface of the head so that
it encircles the plate l4 and sleeve l2‘ to the
same height as the ?ns H. The purpose of this
band is to seal the spigot joint 2| so that dur
ing brazing the molten brazing material is un
able to leak through the joint under the centrif
ugal force to which it is subjected.
The various parts having been treated and as~
sembled as described above, the brazing opera
rial is melted in an iron pot 40 which, as shown
in Figure 2, is provided with a spout for pouring
the molten material from the bottom of the pot.
When the head has reached the required tem
perature (which is indicated to the operator by
the melting of a small strip of the brazing ma
terial lying upon the portion N5 of the face IS)
the platform 24 is brought to rest and the con
tents of the pct 40 are poured into the head as
sembly. The molten brazing material is poured
on to the plug adaptors 2|) and over the joints
between the tray |8 and the ?ns |'|. When the
contents of the pot 40 have been introduced to.
the head assembly the electric motor is started
tion is now performed.
15 and during the subsequent two minutes the as
sembly is twice speeded up from rest to the max
The apparatus which is provided for this pur
imum speed of 350 R. P. M.—at which the molten
pose is shown in Figure 2 and comprises base
brazing material reaches the top of the ?ns.
[plate 22, a pedestal bearing 23 carried by the
When the second speeding up of the platform
base plate, a rotatable platform 24 supported
from the bearing 23 by the shaft 25, a pulley 26 20 24 has been accomplished the speed of the plat
form is reduced to 150 R. P. M. and the burner
which is suitably driven by a belt 27 so as to
28 ‘is extinguished. The speed is maintained un
rotate the platform 24, a gas burner 28 disposed
til the temperature of the head assembly has
below the platform 24 and supported upon legs
fallen well below the melting point of the braz
29, and a cylindrical shield 30 which rests upon
the legs 29 and envelops the gas burner, the 25 ing material. The head is then slowly cooled in
platform and the head assembly. Gas passes
In order to clean the inside of the head and to
to the burner 23 by a pipe 3|. The pulley 26 is
remove excess ?ux the whole of the inside sur
driven from an electric motor (not shown) by
face of the sleeve l2, face l5 and the ?ns H are
belt 21, the arrangement being that the speed
Washed with dilute nitric acid and then with
of said motor is variable to vary the speed of
rotation of the platform 24.
The head assembly in preparation for the
brazing operation is mounted on platform 24
and clamped in position thereon. The clamp
water to remove the acid.
In order to relieve any stresses introduced into
the head during cooling from the brazing tem-
perature the ?nished head is subjected to a heat
ing means provided is shown in Figure 2 and 35 treatment at 450° C. for one hour.
It will have been understood from the above
comprises a spider 32 which extends across the
description of the brazing operation that the
?ange-end of the sleeve |2, arms 33 which en~
adaptors 2d are secured to the plate I4, that the
gage the spider 32 and the lugs 34 of the plat
sleeve L2 and plate M are united at the spigot
form support 35, and bolts 36 which are capable
of engaging the flange I3 of sleeve I2. When 40 joint 2| and that the ?ns I"! are attached to the
faces l5, l5 and the inner surface of the sleeve
the bolts 3-3 are tightened down the clamping
l2 in a single brazing operation. By varying the
speed of rotation of the platform 24 whilst the
ing the head assembly to the platform 2'4 and of
brazing material is in a molten condition'the
forcing the sleeve l2 into intimate contact with
plate M at the spigot joint 2|.
45 brazing material is made to flow over the sur
faces l5, I'E. Moreover, by selecting a suitable
1 It is also necessary to press the pack of ?ns
speed of rotation for the platform 24 whilst the
|'| into contact with the face l5 of the plate I4
brazing material is solidifying, a predetermined
and to prevent relative movement between said
depth of brazing material is provided over the
pack and the plate during rotation of the plat
form 24. To this end a turn-bolt 31, which is 50 surfaces is and H5. The depth of this layer of
material is such that complete contact is ensured
threaded in the boss of the spider 32, engages a
between the ?ns l? and face |5.
stirrup 38 whose ends rest upon a ring 3!? that
lies upon the upper edge of the pack of ?ns.
It will be noted from Figure 1 that the rings ‘
which are commonly provided to form a seal be
When the bolt 37 is screwed downwardly upon
the stirrup 38 the latter forces the ring 39 55 tween the head ill and the sleeve-valve ‘are
adapted to be carried by a member 4|. This
against the pack of ?ns thereby clamping the
latter in proper relationship upon the plate Hi.
ring carrier, which is of cast iron, is provided
because of the poor Wearing qualities which the
The head assembly having been clamped in
base plate l4 possesses When this is produced
position on the platform 24 as described a quan
tity of the flux dissolved in water is poured into 60 from copper or a copper alloy.
the head assembly. The gas burner 28 is lit,
The carrier 4| may be shrunk upon the plate
the shield 35 placed in position so that hot ma
E4 or alternatively shrunk and brazed thereon.
terial within the head assembly is incapable of
When it is proposed to shrink and braze the
being thrown out against the operator, and the
carrier 4| to the plate l4, a number of holes 43
electric motor is started up. During the heat 05 are drilled from the inclined portion of face IE
ing of the head assembly the speed of rotation
to the stepped portion thereof which receives
of the platform 24 is varied continuously in order
the carrier 4|, these holes being placed around
‘to cause the ?ux to wash over all the surfaces
the periphery of the plate I4. The cast iron car
of the parts to be brazed.
rier is dipped in a bath of molten brazing ma
The heat of the ring 28 is adjusted so that 70 terial so that the latter coats the surface thereof
the time required for the head to reach the braz
which will engage with the plate l4. The other
ing temperature (approximately 730° C.) is
surfaces are protected from the molten material
means described serves a dual function of clamp
about ten minutes.
, Whilst the head assembly is being heated up
as indicated, a quantity of the brazing mate
by a coating of heat resistant cement. The
coated carrier 4| is slowly cooled in air and then
76 the excess brazing material is removed'so that
its diametral dimension will provide an inter
a plurality of cooling ?ns to the base of a junk
with the plate M. The carrier 41 is
then Washed with ?ux, heated and shrunk on to
the plate 24. The head assembly with the car
rier {H is then mounted upon the platform 24
and the brazing operation described above per
formed. The retaining band 42 previously re
ferred to is provided to cover the joint between
head or" a sleeve-valve internal combustion en
gine and the base to a tubular Wall of the head
comprising assembling the ?ns to the base and
the base to the Wall, introducing a ?ux to the
assembled head, heating the assembled head and
simultaneously rotating it to Wash the adjoining
the carrier ti and the plate hi and the spigot
and the walh introducing a. brazing material to
joint 2! se that the molten brazing material is 10 i. e head, rotating the latter
a varying speed
to escape through these two joints.
lst continuing to heat the head to cause the
It is to be understood that although in the em
:n material to ?ow over the junction of the
bodiment described the parts to be brazed to
' and the base and of the base and the wall,
gether are rotated about a vertical axis, this may
<- head, and controlling the speed of
certain cases be done about a horizontal or 15 rotation during the cooling step to determine the
other axis dependent upon the construction of the
parts to be joined.
I claim:
A brazing process for simultaneously uniting
form of the brazing joint between the ?ns and
and between the base and the tubular
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