Improvements in Tube Expanders.
Year: 1892

page_text: Date of Application, 18th Mar., 1892
Complete Specification Left, 19th Dec., 1892-Accepted, 21st Jan., 1893
PROVISIONAL SPECIFICATION.
Improvements in Tube Expanders.
I, JOHN MCKAY of Victoria Avenue, Whitley, in the County of Northumberland,
Engineer, do hereby declare the nature of this invention to be as follows:-
The object of this invention is to provide an expanding tool which will more
efficiently operate upon the very strong tubes now in general use, especially for
stay tubes, in modern marine and other boilers working at very high pressures;
combined with certain minor improvements.
I have found by study of the mechanical theory, confirmed by practical experi-
ments, that the first operation of an expander is to enlarge the tube and cause it
to grip in the hole in the tube plate at certain points which with the ordinary
expander are three, forming an equilateral triangle, and it is only after this first
operation has been effected that the tube is really expanded all round so as to be
made perfectly tight in the tube plate. This first operation, effected by driving in
the tapered mandrel, sets out the tube at three points and with tubes of great
thickness a great strain is put on the material owing to the short distance between
the rollers which form cords of arcs each only one third of the circumference of
the tube. I have found that by using two rollers opposite each other the enlarge-
ment of the tube, to cause it to grip in the hole, is effected with much less
application of power and consequently less strain upon the material of the tube,
owing to the chords being of arcs each of one half the circumference of the tube.
The tube end is now of a slightly elliptical form the longer axis of which is
from one roller to the other and a fulcrum being established the further operation
of the rollers, revolving within the tube, expands it into a circle perfectly tight in
the tube plate.
"
Although I have described the expander with parallel rollers and a tapered
'mandrel," I may use tapered rollers and a parallel or nearly parallel "mandrel "
by which they are revolved and the rollers may be set with their axes inclined to
that of the "mandrel" so as to tend to draw in the "mandrel" when revolved.
I prefer to use grooved rollers as described in my Patent No. 6242 of 1891.
In order to keep the block which carries the two expanding rollers fair centrally
in the tube, guide rollers may be fitted which have no expanding action.
To keep the two rollers in position and prevent them falling inward when the
"mandrel" is withdrawn, I propose to fit in the block an inside bush" wich slots
of sufficient width to allow the "mandrel" to operate but not to allow the rollers
to pass through and to prevent the rollers falling out of the block a spring shield
is slipped over the block with lots which will allow the rollers to be expanded
by the "mandrel" but will not allow them to fall out. The slots in the block
will thus be cut straight through instead of being formed with partly overlapping
edges which soon wear away and loose pins or equivalent devices are dispensed
with.
The driving in and withdrawing of the "mandrel" may be facilitated by
prolonging the shank outside the tube plate and fitting it with a heavy sleeve
block to run freely upon it so that the workman, using the block as a hammer, by
impact against the enlarged collar part of the "mandrel" can drive it in and
continue to drive it with one hand while with the other hand he simultaneously
revolves it, the double action being in my opinion likely to facilitate the operation
of expanding; and when the "mandrel is to be withdrawn the reverse action o:

page_text: the sliding hammer upon an outer collar will start it without injuring the tool by
hammering it sidewise as is now done.
Dated this 18th day of March 1892.
T. J. DANSON,
By L. W., per F. B.
COMPLETE SPECIFICATION.
Improvements in Tube Expanders.
1, JOHN MCKAY, of Victoria Avenue, Whitley, in the County of Northumber-
land, 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:-
The object of this invention is to provide an expanding tool which will more
efficiently operate upon the very strong tubes now in general use, especially for
stay tubes, in modern marine and other boilers working at very high pressures;
combined with certain minor improvements.
I have found by study of the mechanical theory, confirmed by practical
experiments, that the first operation of an expander is to enlarge the tube and
cause it to grip in the hole in the tube plate at certain points which with the
ordinary expander are three, forming an equilateral triangle and it is only after
this first operation has been effected that the tube is really expanded all round so
as to be made perfectly tight in the tube plate. This first operation, effected by
driving in the tapered mandril, sets out the tube at three points and with tubes of
great thickness a great strain I put on the material owing to the short distance
between the rollers which form chords of arcs each only one third of the circum-
ference of the tube. I have found that by using two rollers, opposite each other
the enlargement of the tube, to cause it to grip in the hole, is effected with much
less application of power and consequently less strain upon the material of the tube,
owing to the chords being of arcs each of one half the circumference of the tube.
The tube end is now of a slightly elliptical form the longer axis of which is from
one roller to the other and a fulcrum being established the further operation of the
rollers, revolving within the tube, expands it into a circle perfectly tight in the
tube plate.
Although I have described the expander with parallel rollers and a tapered
"mandril," I may use tapered rollers and a parallel "mandril" by which they are
revolved or both rollers and mandril may be parallel and the rollers may be set
with their axes inclined to that of the "mandril" so as to tend to draw in the
"mandril" when revolved. I prefer to use grooved rollers as described in my
Patent No. 6242 of 1891.
In order to keep the block which carries the two expanding rollers fair centrally
in the tube, guide rollers may be fitted which have no expanding action.
To keep the 2 rollers in position, and prevent them falling inward when the
"mandril" is withdrawn, I propose to fit in the block an inside "bush" with slots
of sufficient width to allow the "mandril" to operate but not to allow the rollers to
pass through and to prevent the rollers falling out of the block a spring shield is
slipped over the block with slots which will allow the rollers to be expanded by
the "mandril" but will not allow them to fall out. The slots in the block will
thus be cut straight through instead of being formed with partly overlapping edges
which soon wear away and loose pins, or equivalent devices, are dispensed with.
The driving in and withdrawing of the "mandril may be facilitated by pro-
longing the shank outside the tube plate and fitting it with a heavy aleeve block to
run freely upon it so that the workman, using the block as a hammer, by impact
against the enlarged collar part of the "mandril" can drive it in and continue to
drive it with one hand while with the other hand he simultaneously revolves it the
double action being in my opinion likely to facilitate the operation of expanding
לי

page_text: hammer upon an outer collar will start it without injuring the tool by hammering
it sidewise as is now done.
DESCRIPTIONS OF DRAWINGS.
On the sheet of drawings herewith I illustrate my invention in the various forms
in which I propose to carry out the application of two rollers with details of the
minor improvements referred to in my Specifications with 3 diagrams shewing the
operation of two rollers and of three rollers.
Diagram 1. shews an end view of a tube in the hole in tube plate about th
larger in diameter than the outside of the tube before the expander is applied.
Diagram 2, shews the first operation of 3 rollers upon the tube at the points 1.
2 and 3.
Diagram 3 shews the first operation of 2 rollers upon the tube at the points 1
and 2.
Fig. 1 shews an expander complete with 2 rollers made and fitted according to
my invention and
Fig. 2 is a section through X-X Fig. 1.
A is the block carrying the two rollers B B in slots which are cut only so far
through leaving a shoulder which prevents them falling inward when the tapered
mandril C is withdrawn. The spring shield D is shewn as formed of a split tube
the inward bent edges of which fit into a groove E cut along the block, which
prevent it turning round when it is in position, the edges of the slots FF then
slightly overlapping the diameters of the rollers and preventing them falling
outward. The spring shield is slipped over the block from the inner end and fixed
by a hole in it passing over a slightly projecting stud G. Although the shield is
shewn and described applied as I prefer, its construction and mode of application
may be varied still effecting the object of keeping the rollers from falling outward
without forming overlapping edges in the slot.
On Fig. 3 is shewn a section through the expander in which the rollers B B are
prevented falling inward by an inside bush H slipped into the block the slots in
which may thus be cut straight through. The gauge cap and adjusting collar are
of the ordinary construction. The mandril C is turned round by a bar inserted in
one of the holes J J in the enlarged part and beyond this the mandril is continued
to receive a heavy sleeve block K by the impact of which against the enlarged
part the mandril can be driven in, the reverse action upon the collar K¹ withdrawing
the mandril.
On Fig. 1^ is shewn a portion of the block A but the expanding rollers B B,
instead of being set with their axes parallel with the axis of the mandril, have
their axes slightly angled thereto, the object being to give them a self feeding
action upon the interior surface of the tube and this form, which I consider of
great importance, dispenses with driving in the mandril by force to cause the
rollers to grip when expanding the tube and the sleeve hammer may not be required
except in special cases, such as stay tubes with nuts on the outer ends to enable the
rollers to come out of the tube end.
Figs. 1 and 1 shew this sleeve hammer appliance in modified forms which
explain themselves the sleeve block K in Fig. 1° having long slots L cut
through it which strike against the bar by which the mandril is revolved which
is inserted through the slots L so that the sleeve block K will act by impact
against it in one direction to drive in the mandril or in the reverse direction to
withdraw it.
Figs. 4, 4 and 5, shew modifications of my invention as to the mode of expanding
the two rollers B B.
In Figs. 4 and 4ª the rollers B B are expanded by the action of a short parallel
mandril C which is forced laterally between them by a wedge shaped key M driven
into a recess N cut along the interior of the block A and when the rollers have

page_text: been expanded to their full extent the mandril, then being in the line of their axes,
is prevented going further by coming against the stop cavity O in the block. The
mandril, being revolved by a key applied to its square end, revolves the rollers with
the block in the tube and the wedge being driven out the mandril falls back and the
rollers are released. In Fig. 5 the same expanding action upon the rollers B B is
effected by two intermediate rollers PP which are forced inward between the
rollers B B to an extent sufficient to expand them, by two wedge keys M M driven
into two recesses N N cut along the interior of the block A and the expanding
rollers B B, being revolved by keys applied to their projecting square ends, revolve
the block in the tubo. Fig. 6 shews another form in which instead of revolving the
roller P as a mandril and thus revolving the rollers B B with the block A a canted
end may project outward upon the block and on applying a key the block itself with
the expanding rollers 'may be revolved in the tube and this form is very suitable for
small tubes. In Figs. 4, 44, 5, and 6 the acting mandril C and the rollers B B are
parallel as are also the intermediate rollers P P in Fig. 5. A gauge may be formed
upon the block A at two or more points to fix the position of the rollers in the tube.
as indicated on Figs. 4. 44 and on Fig. 5.
By the application of the wedge M and parallel mandril C shewn on Figs. 4
and 44 very great expanding power is obtained; first by the wedge action upon the
mandril C and then an increased power as the mandril is forced into its extreme
position between the expanding rollers B B and this double wedge action is also
obtained by the method shewn on Fig. 5 which will be found very effective as the
expanding rollers can be revolved independently of the auxiliary rollers and thus
any slight inequality of the tube such as a weld seam would be overcome. The
expanding rollers B B in the case of Figs. 4 and 4ª can be also operated in this
manner by being formed with projecting square ends for a key, with or without the
mandril being made to revolve. Instead of a wedge key to set out the expanding
rollers B B as shewn, I may employ an equivalent wedging device for effecting this
object such as an eccentric mandril operated from outside the block which will by
being rotated through a quarter circle force the intermediate roller or rollers P P
between the expanding rollers.
When it is desired, as sometimes is the case, to form an external bead or beads
on the tube end, either to secure it in the tube plate or, in the flanges on tubes or
pipes the expanding rollers B B in Figs. 4, 4, 5 and 6 may be made with corre
sponding ridges and grooves in the parallel mandril C or in the intermediate parallel
rollers PP the method of wedging out the expanding rollers by a tapered key or
by an eccentric mandril enabling this to be done but this formation of the expanding
rollers is not shown by drawings as it forms no part of my invention.
Having now particularly described and ascertained the nature of said inven-
tion and in what manner the same is to be performed I declare that what-I
claim is-
"
1st. The application to tube expanders of two parallel or tapered rollers,
diametrically opposite each other, and set out radially by the action of a tapered
mandril inserted between them; the two rollers being disposed with their axes
parallel with the axis of the mandril or slightly inclined thereto substantially as
described, and shewn by Figs. 1, 2 and 14.
2nd: In such tube expanders, with two rollers, the application of a parallel
mandril forced laterally between the expanding rollers preferably parallel by the
action of a wedge key (or equivalent device such as an eccentric mandril) the
rollers being revolved around the inside of the tube by revolving the parallel
mandril; or separately revolved without the action of a revolving mandril or the
alternative application of two parallel rollers, one on each side, forced laterally
between the expanding rollers by the action of two, wedge keys (or equivalent
wedging device such as eccentric mandrils) with means whereby the expanding
rollers may be revolved separately, substantially as described and in one form shewn
by Figs. 4. 4 and 5, or the application of one roller, in place of the revolved

page_text: mandril, forced between the expanding rollers by the action of a wedge key (or
equivalent wedging device such as an eccentric mandril) shewn in Figs. 4 and 44
the expanding rollers being separately revolved.
3rd. The alternative application of one parallel roller forced laterally between
the two expanding rollers by the action of a wedge key (or equivalent wedging
device such as an eccentric mandril) with means whereby the expander block, with
the expanding rollers, may be revolved in the tube substantially as described and
shewn by Fig. 6.
4th. The application to tube expanders of a retaining shield, fitting over the
block and secured thereon, with slots the edges of which prevent the expanding
rollers from falling outward substantially as described and shewn.
5th. The application to tube expanders of an internal bush, fitting the interior of
the block, with slots the projecting edges of which prevent the expanding roller
from falling inward when the mandril is withdrawn substantially as described and
shewn by Fig. 3.
6th. The application to the mandrils of tube expanders of a sliding block, or
sleeve hammer, by which the mandril may be driven into the expander to set out
the rollers or withdrawn when the operation of expanding has been completed,
substantially as described and shewn in three different forms by Figs. 1, 18
and 1º.
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