A NEW OR IMPROVED TUBE EXPANDER
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by John Lyall at the Office of the
Commissioners of Patents, with his Petition, on the 31st March
1875.
I, JOHN LYALL, of the City of Glasgow, in the County of Lanark,
North Britain, Boiler Maker, do hereby declare the nature of the said
Invention for "A NEW OR IMPROVED TUBE EXPANDER," to be as follows:-
This Invention relates to the general construction and arrangement
of the parts of a tool for expanding or fixing the ends of iron or other
metal tubes so as to make a close joint between them and the metal
plates through which they pass, or to which they are fixed in steam
boilers or other tubular vessels.
And the nature and novelty of the Invention consist all as follows:-
On a round (or it might be oval, polygonal, or other form of) central
spindle a fixed or movable bevelled concave or convex curved head is
formed, and a short hollow spindle with a second head of corresponding
form to the afore-mentioned head is fitted on the same spindle, and
made to work or slide along the said spindle. Each of these heads have
their larger diameters turned to the opposite ends of the spindle.
Between or on these two heads as bearing surfaces are placed two, three,
or more rollers with bevelled or curved ends to correspond with and fit
these two before-named heads. The outside of these heads are made
parallel, and have a short loose tube fitted over them, having lateral

page_text: openings cut in its circumference to allow the rollers to project beyond
its outside diameter, but not so large as to permit them to fall or wholly
pass out through, but to retain them in equal positions round the tube,
according to their number.
Under one modification a tapered cotter is fitted into and passes
through the said central spindle or the tube, and bears against the base
or outer end of the movable head, and on the tool being inserted into
the end of a tube and the said cotter driven or fed in and bearing hard
against the movable head the heads are made to advance towards cach
other and press out the expanding rollers radially until they are forced
hard against the inside of the tube. The tool is then turned round by
means of a spanner, wrench, or other equivalent, such as a hole with
short wrench bar applied to the end of its spindle head or other
convenient part (the cotter being tightened up as the instrument is
turned), the rollers press hard against, and turning inside the tube swell
or expand it and fit it close to its seat. The cotter is then driven back
so as to cause the heads to recede from one another and slacken the
rollers, when the tool may be withdrawn and inserted into another
tube.
Under another modification the outer end of the central spindle might
be screwed, and have a screwed nut on the same; or one or both of the
before-named heads may be screwed to suit the spindle, or the end of
the outer tube may be screwed and fitted with a nut.
By any of the above modifications or means the tool on being
introduced into a tube and the heads made to advance towards each
other by means of the spindle, nut, or head being screwed up with a
spanner, wrench, ratchet lever, or other equivalent until the rollers
press hard against the inside of the tube, the instrument on being turned
round as above described, and as the swivelling or expansion of the tube
goes on the rollers are kept hard against the inside of the tube by the
spindle, nut, or head being screwed up and kept always tight until the
tube is fitted to its seat.
The tool is withdrawn by slackening the nuts or heads, which allows
the rollers to slacken back, and the instrument to be removed and
inserted into another tube.
The construction of tool preferred is that with a parallel screwed
central spindle, having a bevelled head formed or fixed on one end, and

page_text: a movable or annular bevelled head fitted on to the same spindle, the
larger end of each head being towards the opposite ends of the spindle.
A slightly tapering hole is bored into the large or outer end of the
movable head, and a screwed nut fitted on the spindle, having its inner
or leading end tapering to suit the tapering hole made in the large end
of the movable head as a small friction clutch. The end of the screwed
A short tube is fitted
part of the spindle is reduced to a square.
outside the heads, which keeps the rollers in their places with three
recesses for retaining the rollers in their proper position, all as before
stated. Three rollers are by preference used with bevelled ends to suit
the bevels on the heads.
When the tool is inserted into a tube for expansion the nut is screwed
up, causing both heads to advance towards each other, and pressing out
the rollers hard against the inside of the tube, and as the screwing up
of the nut is continued the instrument will turn round, owing to the
leading end of the nut acting as a friction clutch in the end of the
movable head, thus regulating (in a self-feeding manner) the expulsion
or expansion of the rollers against the inside of the tube. The turning
is continued until the tube is swelled or expanded to completely fix it
in the tube plate. The instrument is relieved from the tube by a wrench
or spanner being applied on the square end of the spindle to keep it
from turning while the screwed head is being unscrewed. This allows
the heads to recede from each other and the rollers to slacken, when the
instrument can be withdrawn.
The advantages of this instrument are a saving of time, no suspension
of working the same being needed either to execute expansion or to
withdraw the instrument after expansion has been accomplished; it
occupies less space, and can be worked with greater rapidity in fire-boxes
and other confined flues or spaces; it can do a greater number of sizes
of tubes without any change of parts; it is self-feeding, and requires no
hammering or drifting.
Although parallel rollers have been described it is to be understood
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