Improvements in Tube-expanding Tools.
Year: 1899

page_text: Date of Application, 2nd Oct., 1899-Accepted, 30th Dec., 1899
Improvements in Tube-expanding Tools.
I, CARE. ANGSTRÖM, Managing Director, of Motala Works, Sweden, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:
The tube-expander here referred to is characterized by a special feeding-device
consisting of a screw located co-axially to the mandrel or plug actuating the
pressure rollers and coupled to said mandrel, on which screw is mounted on the
one hand a sleeve engaging with the outer portion of the tube-expander, which
portion carries the rollers, and, on the other hand, a nut which can be locked
to a case mounted on the aforesaid sleeve and in which is journalled a worm
and worm-gear for driving the screw and pressure-rollers, so as to feed forward
the rotating screw and the mandrel coupled to it. By rotating the nut on the
screw the latter can be moved together with the mandrel, independently of the
worm-gearing, in the rearward direction for releasing the tube-expander on
the completion of the expanding operation. The mandrel is thus fed positively
forward longitudinally when the pressure-rollers are rotated by the gearing, while
on completing the expanding-operation the tube-expander can be quickly released
by a few turns of the nut, which, for this purpose, is provided with a crank.
The latter operation, consequently, can be performed in far less time than with
for instance Yarrow's well-known expander, in which both the feeding and the
return-motion are due to an oblique position (helical motion) of the pressure-
rollers. The present tube-expanding tool is, moreover, fitted with an automatic
disengaging device applied to the power-transmitting parts so as to prevent the
rollers from exerting a greater pressure than necessary for effecting a secure
fastening of the tube.
The drawing annexed shows in
of Figure 2:
Figure 1 the entire tube-expander in section, on the line
Figure 2 being a section on the line y of Figure 1.
Figure 3 shows the nut and the device for locking, and releasing it:
Figure 4 shows the expander viewed from its forward end, and
Figure 5 is a detail.
The tube-expander proper of the "Yarrow" type is composed, as usual, of a
hollow cylinder or cone a with pressure rollers a¹ inserted in apertures, between
which rollers the mandrel a² can be inserted and pushed forward. A prolongation
of the latter is formed by a screw on which is mounted a sleeve b¹ which, by means
of a key is caused to take part in the rotation of the screw. The mandrel
and the screw are coupled together by means of a split ring a' engaging in a
slot in the screw and embracing the spherically-rounded head of the mandrel,
as shown in Figure 1. The screw can revolve freely in relation to the mandrel.
The ring at is divided diametrically in two halves, (Figure 5), and the coupling is
effected in such manner that the two halves of the ring are made to embrace the
mandrel and screw, whereupon the cylinder a is slidden over the ring and pushed

page_text: further on to the screw, to the sleeve of which it is coupled by means of a
key and set-screw a. Figure 5 shows the ring at viewed from one end. On
the sleeve is mounted a worm-gear c with which engages a worm c¹ to which
power is transmitted by means of a flexible shaft or in some other manner. The
gear and worm are protected by a casing fitting on to the sleeve b¹ and provided
with a cover c³. The casing c² is held in place by a ring et screwed on to the end
of the sleeve. Close to the said parts is situated a nut screwed on to the screw b
and provided with a crank b. By means of a collar the nut extends over a
toothed flange projecting above the ring et from the neck of the cover ³, with
which flange engages a pawl d mounted on a pin d of the nut and located in a
recess in the collar. The pawl & can be brought out of engagement with the
flange by revolving a pin which is made of semi-cylindrical section opposite
an extension 3 of the pawl, which is held against the flange by a spring d
In one position the pin d allows the pawl to engage owing to the action of the
spring, while in its other position the reverse condition is brought about.
pin is revolved by a handle d³.
The
In the rotation of the screw by means of the gearing, for expanding a tube,
the sleeve b, cylinder a and its rollers take part, but not the casing and nut 3
engaging with the latter by means of its pawl. Owing to the engagement of the
threads of the nut with the screw b, the latter is fed forward together with the
mandrel ².
If the nut is released and allowed to revolve together with the screw, no
longitudinal movement of the screw and mandrel will take place. On completing
the expansion of the tube, the nut 63 is revolved on the screw b, causing the
latter to be withdrawn together with the mandrel a², whereupon the tool can be
taken out of the tube. The tool is secured by the handle f and the casing f
of the worm-shaft. In said casing is located the automatic disengaging-device.
The latter, the construction of which is already known as applied for other pur-
poses, is composed of two coupling-halves y and g¹ engaging with each other either
by means of teeth of stubbed shape shown in Figure 6 or by simply plain
frictional surfaces. The coupling-halves are held together by a spiral spring h
the tension of which can be adjusted by means of a nut g screwed on to the shaft
portion. When the resistance has reached a certain limit, which, in other
words, means that when the expansion of the tube is complete, the coupling-
halves will slip or slide on each other. The sound produced by the teeth serves
as a signal to the workman that the mandrel should be withdrawn. A friction-
coupling may alternatively be used. By the tube-expander described a large
number of tubes can be expanded in a short time without requiring the attention
of a specially-skilled workman, after the tool has once been suitably adjusted for
the work by means of the ring g³.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. A tube-expanding tool in which the mandrel or plug to be propelled between
the pressure-rollers is fed forward positively and independently of the rotary
portion containing the said rollers by means of a screw located behind it, sub-
stantially as described.
2. A tube-expanding tool in which the mandrel or plug to be propelled
between the pressure-rollers is fed forward and backward longitudinally, inde-
pendently of the rotary portion containing the said rollers, by means of a screw
rotatably coupled to it and also coupled to the rotary portion by means of a
sleeve keyed to the latter, on which sleeve the gear for driving the tube-expander
is secured, the screw, moreover, being provided with a nut adapted to be locked in
place or revolved according as a forward or backward movement of the screw and
imandrel is desired, substantially as described.

page_text: 3. A tube-expander tool consisting of a screw coupled to the mandrel or plug
between the pressure-rollers and provided with a sleeve fitting over it, which
sleeve is provided with a worm-gear with which engages a driving worm journalled
in a casing mounted on the sleeve and surrounding the worm wheel, the screw,
moreover, being provided with a nut adapted to be locked by being coupled to
the said casing or to be revolved by means of a crank or the like attached to it,
according as a forward or backward longitudinal movement of the screw and
mandrel is desired, the said sleeve being keyed on to the screw and coupled to
the rotary outer portion of the tube-expander, containing the pressure-rollers,
substantially as described.
4. A tube-expanding tool having a feed-screw for feeding the tube expander
forward, and worm-gearing for rotating the pressure-rollers in the tube, and
provided with a toothed or friction coupling for transmitting power to the
aforesaid gearing, which coupling is closed by a spring and is adapted to slip
when the resistance between the tube-expander and tube reaches a certain limit,
substantially as described.
5. In combination with a tool as characterised in Claim 3, a toothed flange
arranged on the casing, a pawl adapted to engage with said flange, which pawl
is located on a nut (as b) and serves to lock the nut, and a pin bearing on the
pawl and of such a shape as to admit of the pawl being thrown out of engagement
by turning the pin, substantially as described.
6. The complete tube expanding tool substantially as described or illustrated
in the accompanying drawings.
Dated this 2nd day of October 1899.
BOULT, WADE & KILBURN,
Agents for the Applicant.