Improvements in Tube Expanders.
Year: 1893

page_text: Date of Application, 4th Nov., 1893
Complete Specification Left, 7th Aug., 1894-Accepted, 8th Sept., 1894
Improvements in Tube Expanders.
We, JOHN MCKAY, Engineer, ARTHUR HARDY, Outfitter, ANDREW YOUNG,
Draper and MATTHEW STAFFORD DRYDEN, Master Mariner, trading as
John McKay & Co., Northumberland Chambers, in the City and County of
Newcastle-upon-Tyne, do hereby declare the nature of this invention to be as
follows:-
This invention relates to certain improvements in the construction of tube
expanders such as described in Specifications of the Patents of John McKay
No. 6242 dated 1891 and Nos. 5396 and 15635 dated 1892 whether with two or
more rollers and, as to the operation of the rollers, specially designed for expanding
tubes which are subject to the very high test and working pressures now used by
the process of what is termed "hard" expanding when cold.
It is proposed to make the mandril (which will be preferably parallel) instead of
being circular in section, of a slightly elliptical, triangular or polygonal section,
the sides of the polygon forming arcs struck by larger radii than the radius of
the enclosing circle with the following object.
In the process of expanding a tube into the hole in the tube plate the expanding
rollers, in revolving round the interior of the tube raise up in front of each roller
out of the material of the tube, an almost imperceptible ridge or wave which, as
they continue to revolve, increases until it is only by the surging backward of the
mandril, when tapered, or the application of great force, when parallel, that the
rollers are able to continue to travel round the inside of the tube. Now this
surging or slipping of the mandril, in relation to the rollers, is attended with much
objectionable jerking and shock which is prevented by forming the section of the
mandril" with slight deviations from a true circle or, as an alternative, forming the
expanding rollers themselves with such slight deviations from a true circle which,
in grooved rollers, may be formed by the shape of the grooves, though we prefer
such formation of the "mandril" itself. The effect of such formation is that the
slight ridge or wave raised in front of the rollers is surmounted, as the "mandril"
in revolving brings one of its smailer diameters next one of the rollers which
is thus so far eased as to be enabled to travel onward, partially depressing the
ridge or wave, which the following roller, acted upon by one of the larger
diameters of the mandril, further presses into the substance of the tube and at
the same operation expands the tube end in the tube plate. This formation of the
mandril," especially when parallel, which is that we propose to adopt, also enables
it to be easily inserted and in withdrawing it a slight turn in either direction will
release it from the rollers.
"
The further improvements in the construction of the expander consist in so
fitting the "gauge-cap to the "stock" that it acts as a guard or shield to retain
the expanding rollers in their cavities whilst it has a firm abutment against a
grooved collar on the "stock" into which it engages by a clutch tooth formed
ou it entering a corresponding cavity in the collar (or vice versa) and being
turned round is locked, or as readily unlocked and slipped off the "stock
when the expanding rollers are to be taken out or replaced, and this method
of fixing the " gauge-cap so as to form a "guard' or "shield" and to be
readily detachable from the "stock" is applicable to all types of tube expanders,
whether with two or more rollers, and whether with a tapered or parallel mandril
forming a true circle in section, or with one or more slight deviations as herein-
before described.
22

page_text: +66
"
In conjunction with the "gauge-cap as previously described forming also a.
retaining shield for the rollers we may use a retaining sleeve shield sliding over
the inner end of the stock by a bayonet" joint 'and, when in position, so covering
a portion of the inner ends of the rollers as to secure them from falling out of
their cavities and this fitting will in some cases be necessary.
In the Specification of John McKay's Patent No. 5396 of 1892 was shewn a
novel application of the power of a single wedge key to two roller tube expanders
with parallel "mandrils and it is now proposed by this invention to utilise the
wedge action upon both sides of the parallel or tapered "mandril" with the
following objects:-
1st. To cause the "mandril" to force out the two expanding rollers from either
side.
2nd. To facilitate the introduction and withdrawal of the "mandril" when
required.
Mention has already been made of these improvements so far as relates to the
"mandril" being applicable to any of the existing types of tube expanders
whether with two or more rollers or with parallel or tapered "mandrils." With
reference to tapered "mandrils" it has been proved, after many years' experience,
that they are theoretically and practically wrong in their operation and although
they may be used for tubes of copper, brass or similar soft metals, easily expanded
and in many cases afterwards ferruled, yet, with the very thick tubes required for
the high working pressures in modern steam boilers, and requiring special
expanding tools to make them perfectly tight in the tube plates, without injury by
straining the metal, tapered mandrils, with their varying diameters are totally
unsuitable and injurious for the following reasons. Their powerful differential or
"skewing" action tends to wind up the end of the tube in the tube plate in the
manner of a closely coiled spring always struggling to return to its normal position,
which has been clearly and practically demonstrated by sawing the tube through
behind the tube plate when a gauge mark, previously made across the line of the
cut, will shew by the springing back of the severed portions the extent to which
the material of the tube has been distorted by this action of the tapered
mandril. Nor is this distortion or twisting action confined to the tubes but it
extends to the tube plates as has been proved by the surface plate test the upper
and lower edges of one plate (say the front) being clearly shewn to be out of
winding" with the corresponding edges of the other (say the back) plate to a
very serious extent.
When the whole of the tubes are thus wound up, like so many main-springs, a
tremendous twist is given to the tube plates by their united action, throwing a
crushing strain on one side and tensile on the other, to the detriment of the joints
and "gussets" especially those of the back tube plate. A slight lengthening of
the tubes by forced draught is enough to set them free, then leakage, less or more,
is the result.
In the improved tube expander with a parallel "mandril" slightly elliptical,
triangular or polygonal in section acting upon two rollers between which it is
forced by wedge action and released in the same manner, which is the form which
we propose to adopt for all boilers having iron or steel tubes and working at
high pressures, two wedges are fitted in cavities in the "stock"
opposite each
other and at right angles to the two rollers. The wedges are fitted so that
one being eased back the "mandril" enters readily on that side and between
the rollers, and the wedge being driven in, the "mandrel" forces them apart
against the inside of the tube at two points thus commencing the expanding
process and the "mandril," being now revolved, causes the rollers to travel round
the tube until the whole circumference is expanded and the operation may be
further repeated by driving home the acting wedge a little, thereby forcing the
"mandril" still further between the rollers and so spreading them further apart
and so continuing the expanding.
When the "mandril" is to be released and withdrawn the wedge is simply eased

page_text: back or, if the "mandril" has slipped over the centres of the rollers, the other
wedge being eased back it will come out readily so as to allow the tool to be
removed from the tube but need not be entirely withdrawn being provided with a.
stop on its inner end to keep it in position.
"
In any of the forms previously described this tool may be adapted to effect the
"beading" over of the tube ends by fitting to the outer end of the "stock"
grooved rollers which may replace the gauge cap previously described revolving
with the "stock" and on their own axes by contact with the tube end against
which they are forced with sufficient pressure by the self feeding action of the
expanding rollers which will be set at an angle with the axis of the "mandril."
Coned or tapered rollers may be fitted to cone the tube ends as when ferrules are
afterwards to be used.
Dated this
how 100
COMPLETE SPECIFICATION.
Improvements in Tube Expanders.
JOHN MCKAY, Engineer, ARTHUR HARDY, Outfitter, ANDREW YOUNG,
Draper, and MATTHEW STAFFORD DRYDEN, Master Mariner, trading as
John McKay & Co., Northumberland Chambers, in the City and County of
Newcastle-upon-Tyne, 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 construction of tube
expanders such as described in Specifications of the Patents of John McKay,
No. 6242 dated 1891 and Nos. 5396 and 15635 dated 1892 whether with two or
more rollers and, as to the operation of the rollers, specially designed for expanding
tubes which are subject to the very high test and working pressures now used, by
the process of what is termed "hard" expanding when cold.
It is proposed to make the mandril (which will be preferably parallel) instead of
being circular in section, of a slightly elliptical, triangular, or polygonal section,
the sides of the polygon forming arcs struck by larger radii than the radius of the
enclosing circle with the following object.
In the process of expanding a tube into the hole in the tube plate the expanding
rollers, in revolving round the interior of the tube raise up in front of each roller
out of the material of the tube, an almost imperceptible ridge or wave which, as
they continue to revolve, increases until it is only by the surging backward of
the mandril, when tapered, or the application of great force, when parallel, that
the rollers are able to continue to travel round the inside of the tube. Now this
surging or slipping of the mandril, in relation to the rollers, is attended with much
objectionable jerking and shock which is prevented by forming the section of the
"mandril" with slight deviations from a true circle or, as an alternative, forming
the expanding rollers themselves with such slight deviations from a true circle
which, in grooved rollers, may be formed by the shape of the grooves, though we
prefer such formation of the "mandril" itself. The effect of such formation is
that the slight ridge or wave raised in front of the rollers is surmounted, as the
"mandril" in revolving brings one of its smaller diameters next one of the rollers
which is thus so far eased as to be enabled to travel onward, partially depressing
the ridge or wave, which the following roller, acted upon by one of the larger
diameters of the mandril, further presses into the substance of the tube and at the
same operation expands the tube end in the tube plate. This formation of the
"mandril," especially when parallel, which is that we propose to adopt, also enables
it to be easily inserted and in withdrawing it a slight turn in either direction will
release it from the rollers.

page_text: "
The further improvements in the construction of the expander consist in so
fitting the "gauge-cap to the "stock" that it acts as a guard or shield to retain
the expanding rollers in their cavities whilst it has a firm abutment against a
grooved collar on the "stock" into which it engages by a clutch tooth formed on
it entering a corresponding cavity in the collar (or vice versa) and being turned
round is locked, or as readily unlocked and slipped off the "stock" when the
expanding rollers are to be taken out or replaced, and this method of fixing the
gauge-cap so as to form a "guard" or "shield" and to be readily detachable
from the "stock" is applicable to all, types of tube expanders, whether with two
or more rollers, and whether with a tapered or parallel mandril forming a true
circle in section, or with one or more slight deviatious as hereinbefore described.
63
وو
In conjunction with the " gauge-cap" as previously described forming also a
retaining shield for the rollers, we may use a retaining sleeve shield sliding over
the inner end of the stock by a "bayonet" joint, and, when in position, so covering
a portion of the inner ends of the rollers as to secure them from falling out of
their cavities and this fitting will in some cases be necessary.
In the Specification of John McKay's Patent No. 5396 of 1892 was shewn a
novel application of the power of a single wedge key to two roller tube expanders
with parallel "mandrils," and it is now proposed by this invention to utilise the
wedge action upon both sides of the parallel or tapered "mandril" with the
following objects:-
1st. To cause the "mandril" to force out the two expanding rollers from either
side.
2nd. To facilitate the introduction and withdrawal of the "mandril" when
required.
Mention has already been made of these improvements so far as relates to the
"mandril" being applicable to any of the existing types of tube expanders whether
with two or more rollers or with parallel or tapered "mandrils."
With reference
to tapered "mandrils" it has been proved, after many years' experience, that they
are theoretically and practically wrong in their operation and although they may
be used for tubes of copper, brass, or similar soft metals, easily expanded and in
many cases afterwards ferruled, yet, with the very thick tubes required for the
high working pressures in moderu steam boilers, and requiring special expanding
tools to make them perfectly tight in the tube plates, without injury by straining
the metal, tapered mandrils with their varying diameters are totally unsuitable and
injurious for the following reasons. Their powerful differential or "skewing "
action tends to wind up the end of the tube in the tube plate in the manner of a
closely coiled spring always struggling to return to its normal position, which has
been clearly and practically demonstrated by sawing the tube through behind the
tube plate when a gauge mark, previously made across the line of the cut, will
shew by the springing back of the severed portions the extent to which the
material of the tube has been distorted by this action of the tapered mandril. Nor
is this distortion or twisting action confined to the tubes but it extends to the tube
plates as has been proved by the surface plate test the upper and lower edges of
one plate (say the front) being clearly shewn to be out of "winding" with the
corresponding edges of the other (say the back) plate to a very serious extent.
When the whole of the tubes are thus wound up, like so many main-springs, a
tremendous twist is given to the tube plates by their united action, throwing a
crushing strain on one side and tensile strain on the other, to the detriment of the
joints and "gussets" especially those of the back tube plate. A slight lengthening
of the tubes by forced draught is enough to set them free, then leakage, less or
more, is the result.
In the improved tube expander with a parallel "mandril" slightly elliptical,
triangular or polygonal in section acting upon two rollers between which it is forced
by wedge action and released in the same manner, which is the form which we
propose to adopt for all boilers having iron or steel tubes and working at high
pressures, two wedges are fitted in cavities in the "stock" opposite each other and

page_text: at right angles to the two rollers. The wedges are fitted so that one being eased
back the "mandril" enters readily on that side and between the rollers, and the
wedge being driven in, the "mandril" forces them apart against the inside of the
tube at two points thus commencing the expanding process and the "mandril,"
being now revolved, causes the rollers to travel round the tube until the whole
circumference is expanded and the operation may be further repeated by driving
home the acting wedge a little, thereby forcing the "mandril" still further
between the rollers and so spreading them further apart and so continuing the
expanding.
When the "mandril" is to be released and withdrawn the wedge is simply eased
back, or, if the "mandril" has slipped over the centres of the rollers, the other
wedge being eased back, it will come out readily so as to allow the tool to be
removed from the tube but need not be entirely withdrawn being provided with a
stop on its inner end to keep it in position.
"
In any of the forms previously described this tool may be adapted to effect the
'beading over of the tube ends by fitting to the outer end of the "stock"
grooved rollers which may replace the "gauge-cap" previously described revolving
with the "stock" and on their own axes by contact with the tube end against
which they are forced with sufficient pressure by the self feeding action of the
expanding rollers which will be set at an angle with the axis of the "mandril."
Coned or tapered rollers may be fitted to cone the tube ends as when ferrules are
afterwards to be used.
DESCRIPTION OF DRAWINGS.
Figs. 1, 2, and 3 shew three sections of mandrils. Fig. 1 being slightly elliptical;
Fig. 2 triangular; and Fig. 3 pentagonal.
Figs. 4 and 4ª shew respectively a longitudinal section and cross section of an
expander with parallel "mandril" and parallel rollers for tubes of 3 inches
external diameter.
Fig. 5 shews a longitudinal section of an expander with parallel "mandril" and
rollers for expanding and beading tubes by the same application of the tool for
tubes of 24 inches external diameter Fig. 5 being a detail of same.
Figs. 6 and 7 shew respectively a longitudinal section and cross section of an
expander with tapered "mandril" and tapered rollers the mandril being fitted with
two wedges one on each side. All these figs. are full size.
Fig. 8 shews a method of applying expanders made according to our invention to
expand both ends of a tube at one time by using two expanders operating together,
the scale being one quarter full size.
Referring to Figs. 4 and 4 the mandril A is forced between two expanding
rollers B B by the action of a single wedge key C, working in a groove in the
stock D, the mandril being prevented from going beyond the centre line of the
rollers by the formation of a stop at E in the stock, instead of using a supple-
mentary wedge key to operate the mandril from the opposite side, which we have
found in practice to be unnecessary and adding to the cost of the tool. F is the
gauge-cap which is slipped over the inner end of the stock and abuts against a
solid collar G formed thereon, a stud H, screwed or rivetted into the gauge-cap,
entering a slot J in the stock and being turned, to right or left, in the circular
groove K, secures the gauge-cap on the stock in the manner of a bayonet joint.
The gauge-cap sides project beyond the roller cavities and prevent the rollers falling
out when the expander is not in use and each roller has upon its inner end a stud L
which takes into a recess M in the cavity and thus the rollers are properly secured
without any further fitting though retaining sleeve shields may be used instead, as
described in the Specification of the previous Patent already referred to No. 5396,
1892, or in the form shewn and described in the Specification of the previous
Patent No. 15635, 1892, or a partial shield for retaining the inner ends of the
rollers in their cavities may be applied slipping on to the stock by a bayonet joint

page_text: fitting, or the rollers may be inserted from the inside of the stock and prevented
from coming out by turning in the mouths of the cavities to form lips.
. Referring to Fig. 5 the stock D instead of the gauge-cap F carries on its outer
end two rollers N, which may be grooved, bevilled or flat, and these, bearing upon
the tube end, while the expanding is effected, revolve with the stock and also upon
their own axes, beading over the tube end as the expanding proceeds, the tool
feeding in automatically by the expanding rollers B B being set at an angle with
the mandril. When the expanding has been effected to the proper extent it is
stopped by a gauge O, of variable thickness, which comes against the outer end of
the stock and against which the head of the wedge key Cabuts. From this point
the further beading of the tube end proceeds to completion by revolving the stock
and the beading rollers, which will preferably be done from the opposite end of the
tube, and at the same time causing the stock with the beading rollers to feed
forward at a suitable rate to bead the end of the tube against the tube plate
forming a half round bead, as on left hand side of the drawing, or a flush bead
into a slight countersunk in the hole in tube plate as shewn on right hand side by
coned rollers. The revolving and feeding in of the stock and beading rollers may
be effected in different ways, that which we have shewn being convenient and simple
of application and operation by boiler smiths. It consists in attaching to the end
of the stock by a bayonet joint (see Fig. 5A) preferably double, a tube P, extending
through the boiler tube and fitted at the opposite end with a screwed plug Q,
working in a tapped nut R, bearing against the back tube plate, the thread being
proportioned to give the proper amount of feed. Beyond the screwed portion the
plug extends and has in it two holes at right angles for the insertion of a bar which
being turned by the workman revolves the tube P with the stock D and the beading
rollers N, and at the same time forces the latter against the tube end, gradually
effecting the required beading thereof, when, the nut R, being screwed off the end,
the expander with the tube N can be drawn back out of the completed tube and
inserted into the next and the nut replaced.
On Figs. 6 and 7 is shewn an expander with a tapered mandril A, and corre
spondingly tapered rollers B B, to ensure equal rolling action in expanding and
slightly taper the end of the tube, which will facilitate the insertion of ferrules
when required as in brass or copper tubes, to which the tool is specially applicable.
Two wedge keys C C are inserted in the stock D, one on each side of the mandril,
but these are driven home in the first instance and serve only to release the mandril
when the expanding is completed, when a forked lever being inserted under the
heads of the tapered keys, they are easily withdrawn sufficiently to allow the
mandril to come out of the stock and the expander to be removed to another tube.
On Fig. 8 we shew the application of two expanders to a tube so as to expand
both ends together, the mandrils A A being connected by rods, S S, jointed for
convenience of application and packing, so that when either mandril is revolved
and the wedge key, at each end, driven slowly forward, the rollers B B will be
revolved by the mandril, and simultaneously gradually set out by the mandril being
forced between them so that both ends of the tube are expanded by one operation
of the two tools acting simultaneously. At one end the expander is shewn with a
single tapered key, and at the other end with double keys, as either may be adopted,
though a single key is preferred. When the expanding is completed the wedges
are partially withdrawn, releasing the mandrils, when the expander at front end is
drawn out of the tube, bringing with it the jointed rods and the mandril of the
other expander which can then be removed ready for another application. This
application of two expanders will save much time and labour as only one "hand
is required to adjust the tool and drive up the tapered keys at the back end, whilst
the revolving of the mandrils is effected by the usual "hands" at the front end or
in boiler makers' shops, where power is available, the revolving of the mandril may
be effected by the application of such power in any simple way, as by belt or other
gearing.
"

page_text: Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
The improvements in tube expanders comprising:
First. The use of inandrils of elliptical, triangular, pentagonal, or other polygonal
section, with the objects hereinbefore stated.
Second. The construction and method of fitting the gauge-cap abutting against
a solid collar on the stock and against the tube plate, taking the whole working
strain and assisting to retain the expanding rollers in their cavities, substantially as
described and shewn by Figs. 4 and 6.
Third. The improved tube expander comprising in combination a parallel
inandril, two parallel expanding rollers, a tapered wedge key, a gauge-cap abutting
against a solid collar on the stock and assisting to retain the rollers in their cavities,
arranged and operating substantially as hereinbefore described and shewn by
Figs. 4 and 4ª.
Fourth. The application of beading rollers to the stock of an expander with one
wedge key to bead over the ends of the tubes by the same tool, said rollers acting
also as a gauge-cap, substantially as described and shewn by Fig. 5..
Fifth. The improved tube expander comprising a tapered mandril with two
tapered expanding rollers, two wedge keys to release the mandril and rollers and
allow the expander to be withdrawn from the tube when the expanding is completed,
substantially as described and shewn by Figs. 6 and 7.
Sixth. In conjunction with tube expanders having parallel mandrils and two
parallel expanding rollers set out by tapered keys the method of applying two
expanders one at each end of a tube to expand both ends by one operation,
substantially as described and shewn by Fig. 8.
རས་མཁ
T. J. DANSON, F. Inst. P.A.,
Chartered Patent Agent, Newcastle-upon-Tyne, Agent for Applicants.