Improvements in Machinery or Apparatus for Bending Tubes.
Year: 1890

page_text: Date of Application, 27th Dec., 1890
Complete Specification Left, 28th Sept., 1891-Accepted, 31st Oct., 1891
PROVISIONAL SPECIFICATION.
Improvements in Machinery or Apparatus for Bending Tubes.
I, JOHN DONALDSON, a member of the firm of J. I. Thornycroft & Co., Church
Wharf, Chiswick, in the County of Middlesex, Steam Yacht and Launch Builders,
do hereby declare the nature of this invention to be as follows :-
This invention has reference to machinery or apparatus whereby tubes can be
readily and economically bent to curved forms such as those of the tubes for steam
boilers of the kind described in the Specification of Letters Patent granted to
J. I. Thornycroft No. 1404 of 1885. For this purpose upon a suitable table or bed
are fixed two curved bars (hereinafter called formers) the curvatures of which
correspond respectively to the curvature a finished tube is to have at those parts of
it situated at each side of an intermediate and approximately central curved portion.
Mounted on a slide arranged to work between the above mentioned formers and in
a direction at right angles to the length of the tube to be, bent there is a third
former hereinafter called for distinction the intermediate former; and which may
advantageously be a grooved wheel free to rotate. Adjustable guides are so
arranged in relation to the first mentioned formers that when a straight tube has
been placed between the said formers and guides the latter can be moved into
positions in which passages will be formed between them and the formers, then
whilst the intermediate former is benling the intermediate or approximately central
portion of the tube, the other portions thereof will be partly drawn through the
passages referred to, and in this way will be caused to assume curved forms corre-
sponding respectively to those portions of the formers located between the guides
and the intermediate former. To produce a boiler tube of the kind referred to that
part of the one former which corresponds to the portion of tube between the
intermediate or approximately central part and a point near the one end of the
former has the shape of an arc of a circle. To bend one end of the tube around
this circular portion of the former there is provided a wheel or roller carried by a
radial arm adjustable radially in a holder that can be partly rotated. The end of
the former is of irregular shape and for the purpose of bending a tube to corre-
spond, there is a roller journalled in a bracket carried by a slide arranged to move
in a direction at right angles or approximately so to the first mentioned slide. To
bend the other end of the tube another roller is provided, operated by a slide
arranged to work in a direction parallel to the first mentioned slide. To enable this
end of the tube to be partly bent back upon itself, as is necessary for some of the
tubes for a steam boiler of the kind referred to, an adjustable block is provided for
holding the tube against the extreme end of the corresponding former whilst the
unsupported end of the tube is bent to the desired extent by a block having
straight acting surface and carried by a slide. To adapt the machine to bend tubes
to different curvatures, the formers are made removable and a number of different
formers are provided to suit the several forms of tubes to be produced.
a
1 consider it advantageous that those surfaces of certain parts of my apparatus
that bear against the tube whilst it is being bent should be grooved to a form corre-
sponding with the external form of the tube in cross section. The several slides
and the radial arm are operated by any suitable mechanism and means are or may
be provided for operating them in an automatic manner and in the proper order.
As will be obvious machinery or apparatus according to this invention may be
modified to adapt it to bend tubes to various shapes.
Dated this 27+1. dow of December 1800
t "
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.

page_text: *COMPLETE SPECIFICATION.
Improvements in Machinery or Apparatus for Bending Tubes.
1,JOHN DONALDSON, a member of the firm of J. I. "Thornycroft & Co., Church
Wharf, Chiswick, in the County of Middlesex, Steam Yacht and Launch Builders,
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 has reference to machinery or apparatus whereby tribes can be
readily and economically bent to curved forms such as those of the tubes for steam
boilers of the kind described in the Specification of Letters 'Patent granted to
J... Thornycroft No. 1404 of 1885.
For this purpose upon a suitable table or bed are fixed two curved bars (hercin-
after called formers) the curvatures of which correspond respectively to the
..curvature.a.finished tube is to have at those parts of it situated at each side of an
intermediate and approximately central curved portion. Mounted on
a slide
arranged to work between the above mentioned formers and in a direction at right
angles to the length of the tube to be bent there is a third former hereinafter called
for distinction the intermediate former; and which may advantageously be a grooved
wheel free to rotate. Adjustable guides are so arranged in relation to the first
mentioned.formers that when a straight tube has been placed between 'the said
formers.and, guides the latter can be moved into positions in which passages will be
formed between them and the formers, then whilst the intermediate former is
bending the intermediate or approximately central portion of the tube, the other
portions thereof will be partly drawn through the passages referred to, and in this
way will be caused to assume curved forms corresponding respectively to those
portions of the formers located between the guides and the intermediate former.
To produce a boiler tube of the kind referred to, that part of the one former which
..corresponds torthe portion of tube between the intermediate or approximately central
part and a point near the one end of the former, has the shape of an arc of a circle.
To bend one end.of the tube around this circular portion of the former there is
provided a wheel.or roller carried by a radial arm. adjustable radially in a holder
..that can be partly.rotated. "The end of the said former. is in some cases of irregular
shape, and for the purpose of bending a tube to correspond, there is a roller
journalled in a bracket carried by a slide arranged to move in a direction at right
angles or approximately so to the first mentioned slide. To bend the other end of
the tube, another roller or a block is provided, operated by a slide arranged to work
.in a direction parallel to the first mentioned slide. To enable this end of the tube
to be partly bent back upon itself, as is necessary for some of the tubes 'for a steam
.boiler, of the kind referred to, an adjustable block is provided for 'holding the tube
against the extreme end of the corresponding former whilst the unsupported end of
the tube is bent to the desired extent by a block having a straight acting surface
..and.carried by, a slide.
In the accompanying drawings,
Figs. 1, 2 and 3 are respectively a side elevation, an end elevation, and a plan of
a. tube bending machine or apparatus constructed according to this invention.
Eigs. 4.and 5.are plans shewing means whereby the ends of a 'tube can be 'bent
..to certain; special forms when desired.
Fig. 6 is a plan shewing a modified construction of part.of the machine or
apparatus.
Figs. 7 and 8 are detail views.
1 is a table or bed on which are fixed the two curved bars or formers 2, 2ª the
curvatures of which correspond respectively to the curvature a finished tube is to
have at those parts 3 offit situated at each side. of an intermediate and approxi-
mately central curved portion 4. Mounted on a slide 5 arranged to work in guides 6
t

page_text: between the formers. 2, 2, and in a direction at right angles to the length of the
tube to be bent, there is a third or intermediate former 7, which, in the example
shewn is a grooved wheel free to rotate about a pin carried by the slide..
The slide 5 can be reciprocated by any convenient means. In the arrangement
shewn in Figs. 1, 2 and 3 it is operated by a screw shaft 8 driven by bevel
gearing 9 from a shaft provided with a fast pulley 10 and loose pulleys 11 and 12.
13, 13 are belt shifters for the belts 14, 14%, that run on these pulleys and one of
which is crossed.. 15, 15 are rods each provided with a handle 16 whereby either
belt can be shifted from its loose pulley to the fast pulley. 10, or vice versa as well
understood for the purpose of changing the direction of motion of the slide,, or for
bringing the slide to rest, each rod 15, 15 being connected to its corresponding
belt shifter by a lever arm 17 and link 18. In order that the motion of the slide 5
in either direction may be arrested automatically at the desired points of its travel,
the slide is provided with two projections 5", 5".
When the slide 5 is near the
inner end of its stroke, the projection 5" acts against one end of a sliding rod 19,,
the other, end of which then acts against one arm 20 of a lever the other arm 21 of
which is connected by a pin and slot connection to the belt shifter 13 which is
thereby automatically operated to shift the corresponding driving belt from the
fast to the corresponding loose pulley. When the slide is near the outer end of its
stroke, the projection.5 acts against a lever arm 22 and operates the belt shifter 13"
through a lever arm 23, rod 24 and lever arms.25 and 25 to automatically stop the
26 is:
machine. 8 is a wheel whereby, the screw shaft 8 can be rotated by hand.
a block (Fig. 7).that may advantageously be used for firmly holding the tube to be
bent in contact with the intermediate former 7. This block is fixed to a lever 27;
that can be moved in a direction to hold the tube, by a screw threaded rod 28 'and'
hand wheel 29. To release the tube quickly the rod 28 is forked and provided
with a pin 30 that can enter, a recess in one side of the upper end of the lever 27;
so that,, when necessary, the rod can be quickly disengaged from the lever.
In Fig. 6 the slide 5 is reciprocated by the ram 31 of a hydraulic motor 32.
through rods. 33 one of which carries a tappet 34,, which, by acting against a
tappet 35.on the valve rod, stops the motor and arrests the slide when the same
has moved sufficiently inward. 36 is a lever for operating the valve by hand!
37 and. 38 are guides adjustably mounted on the table 1, so that they can be
moved into the positions shewn and form passages with the former 2. A guide
similar to 37, may also be similarly arranged in relation to the former 2: Usually
however the roller 39, hereinafter referred to, can, when moved into the position
shewn as a dotted circle in Fig. 3, be used in lieu of a separate guide.
With the arrangement described, when a straight tube (indicated by dotted lines
in Fig. 3) has been placed between the said formers and guides the latter can be
moved into positions in which passages will be formed between them and the formers,
and then whilst, the intermediate former 7 is moving inward and bending, the
intermediate or approximately central portion 4 of, the tube, the other portions 3
thereof will be partly drawn through the passages referred to, and in this way will
be caused to assume curved forms corresponding respectively to those portions of
A's this
the formers 2, 2ª located between the guides and the intermediate former.
bending action takes place, the guide 38 is adjusted towards the former 2, in. order
that the tube shall closely follow the curvature of the said former.
To produce a boiler tube of the kind referred to, the part 2 of the former 2 has
the shape of an arc of a circle. The two parts 2" and 2° may be in one piece, or in
separate pieces as shewn. To bend the one end of the tube around this circular
portion of the former 2b, there is provided a roller 39 carried by a radial arm 40;
adjustable radially in a holder, 41 that can be partly rotated. For this purpose
the holder carries a worm wheel 42 that gears with a worm 43 that can be rotated
in one direction or the other from a fast pulley 44, through change wheels 45, and
shaft. 46. 47 is a belt shifter for moving a driving belt from the fast pulley 44 to
the loose pulley 48 or vice versa. 47 is another belt shifter operated by hand, for
moving another belt from the, loose pulley 48" to the fast pulley, or vice versa.

page_text: 49 is a handle for operating the belt shifter 47 by hand through a shaft 50,
bevel wheels 51, shaft 52, arm 53 and link 54. 55 is a lever for automatically
actuating the belt shifter 47 to stop the motion of the arm 40 when the
roller 39 nears the end of the tube being bent. For this purpose the lever 55 is
connected by a rod 55ª and bell rank 55 to one end of a rod 56 (see Figs. 1 and 8)
the other end of which is formed with a long slot 57 against the end wall 58 of
which a pin 59 on the holder 41 acts, so as to pull the rod and operate the belt
shifter at the required time. In order that the portion of the tube left projecting
beyond the former 2, after the tube has been acted upon by the intermediate
former 7, may be bent by the roller 39 in the direction of the former 2b, preparatory
to its being hent closely around this former, the roller is pivotted to a carrier 39ª
that can be forced along the rod 40 by an arm 39b actuated by a hand lever 39°.
The shaft 46 carrying the worm 43 is carried by brackets 61 and 62 that may be
adjustably fixed upon the bed 1 to adapt the machine to bend tubes of different
lengths and to different curvatures.. In Fig. 3 the left hand end of the tube is of
circular form to the end. To bend this end of the tube to an irregular form, as is
sometimes necessary, the arrangement shewn in Fig. 4 is adopted. In this arrange-
ment the end of the former 2b is made of the desired irregular shape as shewn, and
for the purpose of bending the end of the tube to correspond thereto, after the tube
has been bent around the circular portion of the former 2 by the roller 39, à
roller 63 is used, journalled in a bracket 64 carried by a slide 65 arranged to move
in a direction at right angles or approximately so to the slide 5.
The slide 65 is
operated by a screw 65" driven by any convenient means, it may be by gearing 66
from the shaft 46 as shewn.
To bend the other end of the tube to the form shewn in Fig. 3, another roller or
a slide block 67 is provided, operated by a screw 68 and crank handle 69.
To
enable this end of the tube to be partly bent back upon itself, as is necessary for
some of the tubes for a steam boiler of the kind referred to, the arrangement shewn
in Fig. 5 can be adopted. In this arrangement an adjustable block 67 is provided
for holding the tube against the extreme end of the corresponding former 2, whilst
the unsupported end of the tube is bent to the desired extent by a pivoted block 70
having a straight acting surface and carried by a slide 71. This slide is operated
in any convenient manner, as for example by a screw 72, driven by worm gearing 73
from a shaft 74 provided with fast and loose pulleys as shewn.
:
To adapt the machine to bend tubes to different curvatures, the formers 2, 2ª, 2
and 7 are made removable and a number of different formers are provided to suit
the several forms of tubes to be produced.
I consider it advantageous that the surfaces of those parts of my apparatus
that bear against the tube whilst it is being bent should be grooved to a form
corresponding with the external form of the tube in cross section. Where the
bend in the tube is acute, it is advantageous that the sides of the grooves should
extend up to or past the semi-diameter of the tube to prevent bulging of the tube.
As will be obvious machinery or apparatus according to this invention may be
modified to adapt it to bend tubes to various shapes.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
:-
1. In a machine or apparatus for bending tubes to curved forms such as herein
referred to, the tube bending arrangement comprising two formers such as 2 and 2ª
fixed to the bed of the machine, an intermediate former such as 7 arranged to work
between the two fixed formers in a direction at right angles to the length of the
tube to be bent, and adjustable guides so arranged in relation to the fixed formers
as with them to constitute passages through which the tube can be partly drawn
by the action of the intermediate former, the arrangement being such as to impart
the desired bent form to the tube, substantially as herein before described.
2. In a machine or apparatus for bending tubes to curved forms, a fixed former

page_text: a part whereof has the shape of an arc of a circle, and a wheel or roller carried by.
a movable radial arm mounted so as to be capable of motion about the centre of
the said circular arc, the arrangement being such that a portion of a tube can be
bent around the circular portion of the said former by the action of the wheel or
roller, substantially as hereinbefore described.
3. In a machine or apparatus for bending tubes, to curved forms, the use in
conjunction with a fixed former of the kind referred to in the preceding claim but
having an irregular shape near one end as shewn in Fig. 4, of a roller or former
mounted upon a slide or carrier and arranged to bend the one end of a partly bent
tube to conform to the irregular shape of the said fixed former when moved towards
the same by the slide or carrier as set forth.
4. In a machine or apparatus of the kind referred to in Claim 1 for bending tubes
to curved forms, the use in conjunction with one of the fixed formers such as 2, of
a slide block or former such as 67 adapted to bend one end of the tube partly
around the said fixed former as set forth.
5. In a machine or apparatus for bending tubes to curved forms, the use in
conjunction with a fixed former such as 2 and an adjustable block for holding one
end of the tube to be bent, against the end of the said formier, of a movable block
having a straight acting surface adapted to bear upon the unsupported end of the
tube and bend the same partly back upon the tube substantially as hereinbefore
described with reference to and shewn in Fig. 5.
6. My improved machine or apparatus for bending tubes to curved forms,
constructed substantially as hereinbefore described with reference to and shewn in
Figs. 1, 2 and 3 of the drawings annexed, or modified according to Fig. 6.
Dated this 24th day of Sentember 1891
JOHN DONALDSON.
W. Lloyd Wise,
46, Lincoln's Inn Fields, London, W.C., Applicant's Agent.