IM- PROVEMENTS IN THE MANUFACTURE OF METAL PIPES OR TUBES, AND IN MACHINERY THEREFOR
Year: 1876

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake, & Co.,
Patent Agents, Southampton Buildings, London, for the Invention of "IM-
PROVEMENTS IN THE MANUFACTURE OF METAL PIPES OR TUBES, AND IN
MACHINERY THEREFOR." A communication from abroad by John Benjamin
Root, of New York, United States of America.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at the
Office of the Commissioners of Patents on the 1st November 1876.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent
Agents, Southampton Buildings, London. "IMPROVEMENTS IN THE MANUFACTURE
OF METAL PIPES OR TUBES, AND IN MACHINERY THEREFOR." A communication.
The essential features of the improvements which constitute the present Invention
are,―
First. Improved mechanism for constructing spirally formed pipes or tubing.
And, Second. The spirally formed pipes or tubes made by said mechanisin, and
with an off-set on one edge of the metal from which the tube or the like is made.
The parts of the improved mechanism which constitute the first part of my
Invention, aside from the standards or supports and adjustable roll frames, are the
following:-
First. A saddle mounted upon the fixed supports, and so constructed and
arranged as to receive simultaneously a circular and a longitudinal reciprocating
movement.
Second. Clamping and feeding mechanism, which is so connected with the saddle
as to partake of its spiral reciprocations, and thus draw the work into and advance
it through the machine with an intermittent motion.
Third. A stationary holding mechanism, which seizes the work and holds it in
position while the feeding devices are performing their alternate backward recipro-
cations.
Fourth. Forming devices for shaping the blank into tubular form as it is advanced
through the machine.
In addition to the above parts, which are capable of producing a spirally formed
pipe with a lock joint, riveting devices are in some instances added, by means of
which a spirally formed lap joint may be riveted.

page_text: .
The roll frame is to be set at an angle with the main axis of the machine, and it
is to be adjustably attached to the bed plate, so that its angle with such axis may
be changed at pleasure, according to the width of the blank that is being worked,
or the size of the pipe that is being made. The rolls, moreover, should be ver-
tically adjustable in the uprights or standards of the roll frame to accommodate the
height of feed to the different sizes of pipe, and each pair of rolls should be
mounted with springs to compensate for any inequality in the work passing between
then. The rolls may also be shaped to give the requisite form to the edges of the
blank, according as it is desired to produce a lap joint or a lock joint in the finished
pipe.
The frame, instead of being provided with rolls for shaping the edges of the
blank, may carry properly shaped dies for this purpose; or if desired the edges of
the blank may be shaped before the blank is placed upon the said frame, in
which case the frame may be regarded simply as a guide frame for giving the
proper support and direction to the blank as it enters the machine, and will not
necessarily carry either rolls or dies.
The saddle is mounted upon circular bearings upon the main upright or sup-
porting standard of the machine, being held to its bearings by rings which permit
of its moving around the main axis of the machine in the arc of a circle, the extent
, of this are of motion being limited by a stop.
The longitudinal movement of the saddle is effected by means of a block and by
.intermediate blocks. A block is secured to an overhanging bracket of the main
supporting standard, being clumped thereto by means of a plate and a set screw, and
it is constructed with a groove in its under face, such groove when the machine is
in action being diagonal to its axis. One of the intermediate blocks, which runs in
the groove of the above-named block, is swiveled upon the back of the other inter-
mediate block, and this block in turn is mounted in a transverse channel in the
back of the said saddle. The face of this channel is curved, but the under face of
the block is plain, consequently the said block is tangential to the face of the
channel; it is connected with the saddle by means of a rock pin playing in a socket
or bearing of the proper size and shape to allow freedom of motion, or in lieu of
such pin the said block may be fitted to the face of the channel in the saddle back
by means of gear teeth.
Rising from the inner end of the saddle is an upright plate, on which is mounted
by suitable adjustable connections the frame of the clamping and feeding mechanism.
This frame, as shown, is gibbed to the plate of the saddle, and can be set at any
desired elevation.
The clamping and feeding devices consists mainly of a clamping bar and the
clamping or pressure rod and their accessories, the said bar acting on the interior of
the pipe, and the pressure rod on the exterior at a corresponding point.
There is a main lever slotted to embrace a bearing block, which rooks on a pivot
connecting it to the bracket which is fastened to the frame of the clamping mechanism.
The inner end of this lever is pivoted to a slide which moves up and down in suitable
ways in the said frame, and this slide operates the long arm of a lever which is
pivoted to the clamping frame.
When the machine is used for making a riveted pipe, the lower end of the
pressure rod is to be armed with a punch, which will punch a rivet hole in the
overlapping edges of the pipe blank with each descent of the punch holder. In
this case it will be advisable to use a shoe, which may be held down upon the seam
by a spiral spring.
This shoe may also be used when the machine is used for making locked pipe,
5
the shoe piece being curved to conform to the curve of the pipe, and to form a
groove in its under face.
The pipe is gripped by the conjoint action of the pressure rod and of the internal
clamping bar, and when thus clamped between the two it will be drawn forward
spirally by the rocking of the saddle and the connected frame of the feeding
mechanism. To hold the pipe while the feeding mechanism after one advance is

page_text: returning to its first position, another clamping mechanism is employed, the principal
parts of which are a lever bar, a lever, and a curved support or ring, against which
the toe of the said lever acts. This holding mechanism is operated by means of a
rod which connects it with the lever of the feeding devices, by which means the
clamping lever is made to engage with and clamp the pipe upon the ring at the
moment when the feeding clamps are disengaged from the pipe preparatory to their
return movement. The connecting rod is attached to the lever with a ball-and-
socket joint, and its connection with the lever is made with a universal joint.
Instead of having the toe of the lever act directly upon the interior of the pipe it
may be provided with a pressure slide moving in ways in the end of the lever bar.
The curved support against which the lever acts is made in the form of a ring.
This form adds to the strength of the parts, and facilitates the holding of the work
while the rivet is being set down by the riveting lever or slide.
A guide band winds spirally around the aforesaid bars in the direction of progress
of the metal, and is connected at both ends with the frame of the feeding mechanism,
so as to partake of all the movements of the same.
The machine, constructed as above described, may be adjusted for working
blanks of different widths, and making pipe of different diameters. For the latter
purpose it will become necessary to change the vertical position of the frame of the
feeding mechanism upon the saddle plate, which is effected by means of slot and
set screw. The lever bar is also made vertically adjustable for the same purpose,
this adjustment being effected by means of a sliding bracket clamped upon the
main upright of the machine at any required height.
A friction block is gibbed to the under side of the overhanging bracket, and is
provided with a set screw for maintaining its bearing upon the back of the saddle.
For inserting rivets in the seam of the pipe after the holes have been punched
I sometimes use a feeding tube, a toothed feed wheel, and fixed guide springs. This
tube is supported in a bracket so located that each halt in the advance of the pipe
brings a punched hole of the seam directly beneath the delivery end of the tube.
The toothed wheel plays through a slot in the side of the tube, and to insure the
more perfect delivery of the rivets a slip ring may be used.
The main lever may be worked by hand, or it may be attached to a crank, and
thus worked by any desired power.
The above-described machine will be found specially adapted for use in making
welded pipe.
I sometimes use a mandril within the pipe to receive the pressure of the aforesaid
lever or its connected slide.
In making use of this modified construction the rivets preferably are inserted
from the inside of the pipe; I therefore use a rivet tube curved in parts to enable it
properly to enter the pipe and discharge the rivets into the holes of the seam.
This aforesaid lever may be forked and bent, and pressed against the seam of
the pipe, the forks of the lever permitting the rivet shank to pass between them,
while a hammer heads the rivet down.
When any of the herein-before described mechanism is used for forming pipe
with a lock joint the interlocking of the edges of the blank previously shaped
therefor by properly constructed rolls of the roll frame or otherwise will be assisted
by means of a shoe and tucker.
The second part of my Invention, as herein-before stated, relates to the pipes or
tubes made by the above-described mechanism, the edges of the blank strip of metal
forming the pipes or tubes being united in a seam that passes spirally around the tube,
and having an off-set formed on one edge of the straight blank of which the tube is
made, so as to make a lap joint, and at the same time leave the interior of the tube
of uniform diameter throughout, the lap joint being secured by rivets.
A plain strip or ribbon of metal is taken having straight and parallel edges, one
of which is off-set. The blank is then wrapped or wound spirally around a cylin-
drical mandril or former, one edge overlapping the other edge. The spiral lap joint

page_text: thus produced may be closed and secured by soldering, galvanizing, welding or
riveting, or the joint may be both riveted and afterwards soldered.
The above mode of forming the spiral lap makes an exceedingly simple joint, and
one that is specially adapted to permit the use of rivets, and the rivets in turn
add greatly to the strength and durability of the seam.
The interior of the tube may have an even surface throughout, the rib being
formed on the exterior, or if desired the rib upon the finished tube will be upon the
inside, while the exterior will be left smooth.
Whether the rib be made on the exterior or the interior it becomes necessary in
forming a spirally wound pipe of uniform diameter from a straight blank by lapping
the edges as contradistinguished from scurfing or bevilling them, that one edge be
struck up or off-set, otherwise it would be impossible to wind it upon the mandril.
This tubing, like any other spirally wound sheet-metal tubing, may be made of
any desired length, one strip being locked or riveted or otherwise joined to
another.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said William Robert Lake in the Great Seal Patent Office on the 1st May
1877.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN THE MANUFACTURE OF
METAL PIPES OR TUBES, AND IN MACHINERY THEREFOR." A communication from
abroad by John Benjamin Root, of New York, United States of America.
The said Invention relates,―
First. To improved mechanism for constructing spirally formed pipes or tubing.
And, Secondly. To the spirally formed pipes or tubes made by said mechanism,
and with an off-set on one edge of the metal from which the tube is made.
In the accompanying Drawings,-
Figure 1 is a plan of a machine constructed according to the first part of the
said Invention; Figure 2 is a vertical longitudinal section of the same.
Figure 3 is an elevation looking towards the saddle end; and Figure 4 is an
elevation looking towards the delivery end of the said machine.
Figure 5 is a vertical longitudinal elevation partly in section of modifications of
the construction shown in Figures 1 and 4.
Figure 6 is an end elevation of such modifications.
Figure 7 shows a further modification of the said Invention.
Figure 8 is a partial plan of the said machine as used for making pipes with a
locked joint, being specially designed to show the shoe and tucker herein-after
described.
Figure 9 is a sectional view of a rivet feeding tube with a toothed feed wheel
herein-after described.
Figure 10 is a sectional view of the rivet tube with slip ring for aiding the
discharge of the rivets as herein-after described.
Figure 11 is an end view of the said tube, slip ring, and ring lever.
Figure 12 is a section of pipe formed from a strip of sheet metal, according to
the said Invention; Figure 13 is a longitudinal section of the same; and Figure 14
is a transverse section of the blank from which it is formed.
Similar letters indicate corresponding parts throughout the Drawings.
The essential features of the improvements in machinery or mechanism which
constitute the first part of this Invention are the following, namely,
First. A saddle mounted upon the fixed supports, and constructed and arranged
to receive simultaneously a circular and a longitudinal reciprocating movement.
Second. A clamping and feeding mechanism, so connected with the said saddle

page_text: as to partake of its spiral reciprocations, and thus draw the work into and advance
it through the machine with an intermittent motion.
Third A stationary holding mechanism, which seizes the work and holds it in
position while the feeding devices are performing their alternate backward recipro-
cations.
Fourth. Forming devices for shaping the blank into tubular form as it is
advanced through the machine.
And, Fifth. The combination of these features in the machine, as shown in the
Drawings and as herein-after set forth.
In addition to the above devices, which are capable of producing a spirally
formed pipe with a lock joint, the said improvements comprise the combination
with the said machine of riveting devices, by means of which a spirally formed lap
joint may be riveted, as herein-after described.
Referring to Figures 1 to 11, A is the roll frame, over which the blank passes on
its way to the main machine; B is the bed plate; C, the main standard or upright;
D, the saddle; E, the adjusting block for determining the longitudinal throw of the
saddle; F, the main frame of the clamping and feeding mechanism; G, the clamping
bar; Hand I, the clamping rod and shoe; J, the lever bar of the holding or riveting
mechanism; K, the compound lever of the same; L, the connecting rod between the
clamping or feeding devices and the holding devices; M, the main lever for operating
the feeding and the holding devices; N, the slide intermediate between the main
lever M and the lever O of the feeding devices; P, a ring through which the pipe
passes, and which forms a part of the holding or riveting mechanism; R, an
adjustable bracket for regulating the position of the lever bar J; S, the rivet
feeding pipes; T, a guide band or strap.
The roll frame is to be set at an angle with the main axis of the machine, and is
to be adjustably attached to the bed plate, so that its angle with such axis may be
changed at pleasure, according to the width of the blank that is being worked or
the size of pipe that is being made.
The rolls, moreover, should be vertically adjustable in the uprights or standards
of the roll frame to accomodate the height of feed to the different sizes of pipe,
and each pair of rolls should be mounted with springs to compensate for any inė-
quality in the work passing between them.
The rolls may also be shaped to give the requisite form to the edges of the blank,
acccording as it is desired to produce a lap joint or a lock joint in the finished
pipe.
These various features in the construction of the roll frame form no part of the
present Invention; they are referred to here simply to show their relation to the
improvements to be herein-after described.
The frame A, instead of being provided with rolls for shaping the edges of the
blank, may carry properly shaped dies for this purpose; or if desired the edges of
the blank may be shaped before the blank is placed upon the frame A, in which
case the frame A may be regarded simply as a guide frame for giving the proper
support and direction to the blank as it enters the machine, and will not necessarily
carry either rolls or dies.
The saddle D is mounted upon circular bearings upon the main upright or
supporting standard of the machine, being held to its bearings by rings a, a, which
permit of its moving around the main axis of the machine in the arc of a circle, the
extent of this arc of motion being limited by the stop b.
The longitudinal movement of the saddle is effected by means of the block E,
and by the intermediate blocks c and d. The block E is secured to the overhanging
bracket of the main supporting standard, being clamped thereto. by means of the
plate and a set screw, and it is constructed with a groove in its under face, such
groove when the machine is in action being diagonal to its axis. The block c,
which runs in the groove of the block E, is swivelled upon the back of the block d,
and the block d in turn is mounted in a transverse channel in the back of the
saddle. The face of this channel is curved, but the under face of the block d is plain,

page_text: consequently the block is tangent to the face of the channel. It is connected with
the saddle by means of the rock pin g playing in a socket or bearing of the proper
size and shape to allow freedom of motion; or in lieu of such pin the block & may
be fitted to the face of the channel in the saddle back by means of gear teeth.
The result of the foregoing construction and arrangement of parts is that when-
ever the saddle is rocked around its axis it is also caused to move longitudinally
on its bearings. The extent of this longitudinal movement will depend upon the
obliquity of the groove in the under face of the adjusting block E to the axis around
which the saddle rocks, and the angle between these parts can be changed at
pleasure by means of the clamping device f according to the requirements of the
work.
Rising from the inner end of the saddle is an upright plate i, on which is mounted
by suitable adjustable connections the frame F of the clamping and feeding
mechanism. This frame, as shown in the Drawings, is gibbed to the plate i of the
saddle, and can be set at any desired elevation according to the size of the pipe
being made by means of the set screw j working in an upright slot in the plate i.
The clamping and feeding devices consist in general of the clamping bar G, and
the clamping or pressure rod H and their accessories, the bar G acting on the interior
of the pipe, and the pressure rod H on the exterior at a corresponding point. As
shown in the Drawings these accessories consist of the main lever M, the slide N, the
lever O, and the shoe I. The lever M is slotted to embrace a bearing block K which
rocks on a pivot connecting it to the bracket 1, which is fastened to the frame F.
The inner end of the lever M is pivoted to the slide N which moves up and down
in suitable ways in the frame F, and this slide operates the long arm of the lever O
which is pivoted to the frame F. The short arm or toe of the lever O acts upon
the head of the pressure rod H to depress it whenever the outer end of the main
lever M is depressed; when the pressure is taken off from the rod H it is returned
to its normal position by a coiled spring acting against the upper face of the
bracket m.
When the machine is used for making a riveted pipe the lower end of the
pressure rod H is to be armed with a punch which will punch a rivet hole in the
overlapping edges of the pipe blank with each descent of the punch holder. In
such case too it will be found advisable to use a shoe I, which may be held down
upon the seam by a spiral spring acting against the under face of the bracket m,
when the punch is withdrawn, and thus prevent the upper lap of the metal from
drawing up with the punch.
This shoe may also be used with advantage when the machine is used for making
locked pipe; in such case instead of bringing the end of the pressure rod H to bear
directly upon the interlocked edges of the metal for setting them down permanently
the shoe piece may be interposed, and for this purpose it will be found advisable to
curve it to conform it to the curve of the pipe, and to form a groove in its under
face of substantially the shape of the finished seam, this groove being turned to
conform to the direction in which the seam is travelling, and the face of the shoe
being of sufficient extent to pinch down all parts of the seam.
Whether the pressure rod is armed with a punch or otherwise it will be seen that
the pipe is gripped by the conjoint action of such pressure rod and of the internal
clamping bar G, and when thus clamped between the two it will be drawn forward
spirally by the rocking of the saddle and the connected frame of the feeding
mechanism.
In order to hold the pipe while the feeding mechanism after one advance is
returning to its first position, another clamping mechanism is employed, the principal
parts of which are the lever bar J, the lever K, and the curved support or ring P
against which the toe of the lever K acts. This holding mechanism is operated by
ineans of the rod L which connects it with the lever Ŏ of the feeding device, by
which means the lever K. is made to engage with and clamp the pipe upon the ring P
at the moment when by the lifting of the lever M the feeding clamps are dis-
engaged from the pipe preparatory to their return movement.
The lever K, as

page_text: shown in Figure 2, is a compound lever, and is pivoted in a slot in the lever bar.
The connecting rod is attached to the lever K with a ball-and-socket joint, and its
connection with the lever O is made with a universal joint.
Instead of having the toe of the lever K act directly upon the interior of the
pipe, it may be provided with a pressure slide n moving in ways in the end of the
lever bar J. The curved support P against which the lever K acts is made in the
form of a ring, this form adding much to the strength of the parts. This form
facilitates the holding of the work while the rivet is being set down by the riveting
lever or slide, the work being clamped between the lever bar and the upper part
of the ring, and the upper part of the ring also takes the strain which arises from
the reaction of the riveting tools.
When a riveted pipe is being made the rivets are inserted in place in the seam
after the work has passed the punch, and before it reaches the holding devices
above described. The further advance of the work carries the rivets successively
under the end of the lever K or the pressure slide operated thereby, and thus each
rivet is firmly headed down or set.
The primary function of the clamping bar G is to act against the pressure rod H,
and thus firmly grip the metal for feeding it forward, but preferably the upper face
of this bar should be curved in a transverse direction to adapt it to act as a
former in shaping the pipe, the metal passing in between this bar and the guide
band or strap T.
The guide band T winds spirally around the bars G and J in the direction of
progress of the metal, and is connected at both ends with the frame of the feeding
mechanism, so as to partake of all the movements of the same.
Instead of being
a mere strip or narrow band as shown, this device may be widened out, so as to
form a concave shield, though for the purpose of ready adjustment to work of
different sizes the narrow band is preferred.
A inachine constructed as above described may be adjusted for working blanks.
of different widths and making pipe of different diameters. For the latter purpose
it will become necessary to change the vertical position of the frame of the feeding
mechanism upon the saddle plate, which is effected by means of the slot and set
screw jas herein-before described. The lever bar J is also made vertically adjust-
able for the same purpose, this adjustment being effected by means of the sliding
bracket R which supports the bar J and can be clamped upon the main upright of
the machine at any required height. Whenever any change is made in the diameter
of the pipe a corresponding adjustment must be given to the guide band T; the
height of the flanging rolls of the roll frame must also be changed; a new supporting
ring P must be provided and the operative length of the connecting rod L must be
changed, which last-named adjustment is effected by means of the set screw o.
A friction block p is gibbed to the underside of the overhanging bracket e and
is provided with a set screw as shown for maintaining its bearing upon the back
of the saddle. The object of this piece is to hold the saddle stationary while the
feeding clamps are parting and the stationary retaining clamps are coming into
play. One means of inserting rivets in the seam of the pipe after the boles have
been punched is shown in Figures 9, 10, and 11, in which S is the feeding tube,
ra toothed feed wheel, and s, 8, 8, s, fixed guide springs. This tube is supported
in a bracket so located that each halt in the advance of the pipe brings a punched
hole of the seam directly beneath the delivery end of the tube." The toothed wheel
plays through a slot in the side of the tube and is to be so connected with the feed
frame or other reciprocating parts of the machine that it will move forward one
step with each novement of such frame or other part. If preferred in order to
ensure the more perfect delivery of the rivets, a slip ring t may be used carrying
springs u, u, u, u. This ring is mounted on a lever, and as it moves up the springs
u, u, snap in behind the head of the rivet, and on its return movement they act as
pushers to force the rivet out between the fixed springs 8, 8. The main lever M
may be worked by hand, which in many small machines for special work will be

page_text: found desirable, or it may be attached by means of a connecting rod to a crank and
thus worked by any desired power.
The above-described machine will be found specially adapted for use in making
welded pipe where the pipe passes directly from the forming machine into and
through the furnace to the welding mechanism. The intermittent action of the
machine gives the requisite pause for the full effect of the hammer or rolls or other
devices employed to effect the welding of the seam.
In Figures 5 and 6 there is shown a modification of the machine as above described,
the chief modification consisting in placing the lever K of the holding and riveting
mechanism below instead of within the pipe (a simple lever of the first order being
substituted for the compound lever shewn in Figure 2) and in using a mandrel
within the pipe to receive the pressure of the lever K or its connected slide n.
stem of this mandrel revolves upon the curved upper face of the bar J¹.
necting rod L is offset where it passes the stem of this mandrel.
The
The con-
In making use of this modified construction, shown in Figures 5 and 6, for
riveted pipes the rivets preferably are inserted from the inside of the pipe. This
necessitates the use of a rivet tube curved in parts, as shown in Figure 5, to enable
it to properly enter the pipe and discharge the rivets into the holes of the seam.
The form of mechanism shown in Figures 5 and 6 has this advantage over that
first described, namely, that the stem of the winding mandrel U can be made hollow
for the passage of water through it to the bulb of a welding mandrel whenever
it is desired to use the machine in connection with a furnace and welding
mechanism.
Where a riveted pipe is to be made by inserting the rivets from the inside, instead.
of using a slide n upon the lever K to set the rivets this lever may be forked and
bent, as shown in the detached views in Figure 7, and thus pressed against the
seam of the pipe, the forks of the lever permitting the rivet shank to pass between
them while a hammer V strikes one or more blows sufficient to head the rivet
down.
When any of the herein-before described mechanism is used for forming a pipe
with a lock joint, the interlocking of the edges of the blank previously shaped
therefor by properly constructed rolls of the roll frame or otherwise will be assisted
by means of a shoe and tucker, as shown in plan and elevation in Figure 8, in
which is the shoe and W the tucker. These parts are to be attached to the feed
frame F at a point just in front of the clamping rod or shoe. As the edges of the
metal interlock they pass into a groove into the shoe piece v, and the tucker W
held against the partially formed seam by any suitable means presses all the parts
thereof well together preparatory to the pinching action of the pressure rod H and
the internal pressure bar G, by which means the seam is turned down and closed.
The second part of this Invention, as before stated, relates to the pipes or tubes
made on the berein-before described mechanism, the edges of the blank strip of
metal forming the pipes or tubes being united in a seam that passes spirally around
the tube and having an offset formed on one edge of the straight blank of which
the tube is made, so as to make a lap joint and at the same time leave the interior
of the tube of uniform diameter throughout, the lap joint being secured by rivets.
Referring to Figures 12, 13, and 14, inclusive, it will be observed that a plain
strip or ribbon of metal is taken having straight and parallel edges, one of which
is offset, as shown at A¹ in Figure 14. The blank is then wrapped or wound
spirally around a cylindrical mandrel or former, the edge A¹ overlapping the edge B¹.
The spiral lap joint thus produced may be closed and secured in any desired mode,
as by soldering, galvanizing, welding, or riveting, or the joint may be both riveted
and afterwards soldered. The Drawing shows it as riveted.
The above mode of forming the spiral lap makes an exceedingly simple joint and
one that is specially adapted to permit the use of rivets, and the rivets in turn add
greatly to the strength and durability of the seam.
As shown in the Drawing (Figures 12 to 14) the interior of the tube will have

page_text: substantially an even surface throughout, the rib being formed on the exterior, but
it is plain that, if desired, the other edge B¹ of the blank may be offset instead of
the edge A¹, and in such way that the rib upon the finished tube will be upon the
inside while the exterior will be left smooth.
Whether the rib be made on the exterior or the interior it becomes necessary in
forming a spirally wound pipe of uniform diameter from a straight blank by
lapping the edges as contra-distinguished from scurfing or bevelling them that one
edge be struck up or offset, substantially as shown, otherwise it would be impossible
to wind it upon the mandrel. This tubing, like any other spirally wound sheet
metal tubing, may be made of any desired length, one strip being locked or riveted
or otherwise joined to another, as shown at C, to an indefinite extent.
Having thus fully described the said Invention as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I claim, the improvements in machinery and in the manufacture of pipes or
tubes, as above specified.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this First day of May, in the year of our Lord One thousand
eight hundred and seventy-seven.
WM. ROB. LAKE. (L.S.)