Technical Field of the Invention
In a first aspect, this invention relates to a roll of
the kind that comprises a drivable roll shaft and two axially spaced-apart stop
rings, one of which is fixed, and the other one is a lock nut, a plurality of other
rings, of which one or more are roll rings, being mounted between the stop rings.
Rolls of the type generally mentioned above, are referred
to as combi rolls by those skilled in the art. In practice, such rolls are used
for hot or cold rolling of long narrow products of metal, such as wires, bars, pipes,
etc. For such purposes, the roll ring or rings, i.e. the very rings which, in contrast
to spacer rings and the like, carry out the forming of the metals are formed with
a number of circumferential grooves, usually having a semi-circular cross section
An important factor for a prolonged proper function of
such rolls is that the different roll and spacer rings are rotationally secured
in relation to each other and in relation to the roll shaft in a reliable way, since
extremely large torques are to be transferred from the shaft to the rings without
the same slipping in relation to each other. In order to overcome this problem,
tightening devices are used, which may be divided into two main categories,
viz. on one hand devices, which utilize the spring force of mechanical springs,
and on the other hand hydraulically acting devices. Of these devices, the last-mentioned
ones are less suitable for many reasons, e.g., the necessity to providing expensive
hydraulic oil conduits to the rotating roll, the risk of oil leakage, etc. Therefore,
mechanical springs are preferable, in so far that they are technically less complicated,
as well as easier and more inexpensive to manufacture, install and use.
In the technique in question, many proposals of mechanical
springs for combi rolls have come up. One of these proposals is disclosed in
, and is based on the use of a Belleville spring in the set of dismountable
rings of the roll shaft. However, this solution has not been successful, among other
things dependent on the placing of the spring inside the set of roll rings and spacer
rings, and because of fatigue problems. It is true that the tension or the spring
force of the Belleville spring in question should be possible to readjust,
viz. by way of a set screw, but as a consequence of the placing thereof inside
the set of dismountable rings, the spring is continuously exposed to forces, which
deform, more precisely flatten the spring, something which fairly fast results in
a slackening or fatigue to such an extent that the spring looses the ability to
instantaneously, during operation, keep the rings pressed against each other with
such a force in the friction joints there between, that the same do not slip. Furthermore,
the inclined spring wears against adjacent rings in such a way that these become
worn in a fairly short time due to the fact that the spring has a (circular) line
contact and not a surface contact, with the rings.
Objects and Features of the Invention
The present invention aims at obviating the above-mentioned
disadvantages of not only the roll presented in
, but also other rolls, which make use of mechanical springs, and at providing
an improved roll. Therefore, in a first aspect, a primary object of the invention
is to provide a roll having a mechanically acting spring device, which can apply
to the dismountable rings of the roll a high spring pressure or a high degree of
prestress, with the purpose of avoiding slipping between the rings during operation,
and which furthermore in a simple way can compensate the inevitable deformation,
which constantly arise in the rings during operation (because of wear and deformation
of the material in the same), so that the high degree of prestress is guaranteed
for the instantaneous transfer of torque between the rings. An additional object
is to provide a roll, the roll width (the axially available space between the fixed
stop ring and the lock nut) of which is utilized in an optimal way by not being
occupied by any space-demanding spring devices. Yet an object of the invention is
to provide a roll in which service in respect of the spring prestress of the rings
may be made in a simple and fast way.
According to the invention, at least the primary object
is attained by the features defined in the characterizing clause of claim 1. A particularly
preferred embodiment of the roll according to the invention is further defined in
In a second aspect, the invention relates to a ring as
such made with built-in spring functions, and intended for the roll according to
the invention. An important object of the invention in this aspect is to provide
a ring, in particular in the form of a lock nut, in which one or more spring devices
are included, which, on one hand, has such a great working range that considerable
deformation in the different rings of the roll can be compensated for, and, on the
other hand, instantaneously, during operation, provide the rings with a high, dynamic
degree of prestress in order to avoid the risk of slipping. An additional object
is to provide a ring made with spring functions, which ring can be mounted on and
dismounted from a roll shaft in a simple way, and which furthermore is made in such
a way that the active spring force of the spring devices can be adjusted in a simple
and ergonomically expedient way.
The above-mentioned objects are attained by way of the
ring, which is defined in the independent claim 3. Preferred embodiments of the
ring according to the invention are further defined in the dependent claims 4-13.
Summary of Invention
The invention is based on the idea of building in into
a ring mountable on a roll shaft, in particular a stop ring in the form of a lock
nut, a spring device in which a mechanical compression spring is included, which
acts between, on one hand, a front press body, which is movable to and fro, in order
to constantly pass on a spring force generated by the compression spring towards
the other rings and, on the other hand, a support body which during the operation
of the roll assumes a fixed position in relation to the ring, but which out of operation
is adjustably movable by way of an adjusting member in order to alter the tension
in the compression spring. Advantageously, a plurality of peripherically spaced-apart
spring devices of this type is arranged in a circular rim formation along the ring.
Brief Description of the Appended Drawings
In the drawings:
Detailed Description of a Preferred Embodiment of the Invention
- Fig. 1
- is a partial longitudinal section through a roll according to the invention,
- Fig. 2
- is an enlarged cross-section through a ring in the form of a lock nut included
in the roll, in which a spring device according to the invention is built-in,
- Fig. 3
- is a cross section showing only a hollow space in which the spring device is
- Fig. 4
- is an exploded view showing the different components included in the spring
- Fig. 5
- is an enlarged section of a compression spring included in the spring device.
In Fig. 1, a combi roll is shown, which in a conventional
way includes a drivable shaft or roll shaft 1 having two axially spaced-apart stop
rings 2, 3, one of which, viz. the stop ring 2, is fixed, while the other one is
a lock nut 3, which is dismountable from the shaft. In the example, the fixed stop
ring 2 is in the form of a ring-shaped shoulder integrated with the rest of the
shaft. However, it is also feasible to make the fixed stop ring 2 in the form of
a separate, dismountable ring, which in a suitable way is axially locked in relation
to the shaft.
Between the fixed stop ring 2 and the detachable lock nut
3, a number of dismountable rings is arranged, of which certain are roll rings 4,
and certain are spacer rings 5. Between the lock nut 3 and the roll ring 4 positioned
closest to the same, there is an additional ring 6, the design of which may deviate
from the design of the spacer rings 5, and which below is referred to as tightening
ring. Generally, the roll shaft 1 as well as the different rings have a rotationally
symmetrical, more precisely cylindrical, basic shape, the rings being delimited
by planar end contact surfaces. Of the end surfaces, only the opposite end surfaces
of the lock nut 3 are provided with reference designations 7, 8, as is seen in Figs.
2 and 3. On the cylinder-shaped inside thereof, the lock nut (see Fig. 1) is formed
with a female thread 9 that is in engagement with a male thread 10 of the roll shaft.
The roll rings 4, which have the purpose of providing the direct roll forming work,
and which for this purpose have circumferential, peripheral grooves 11, may advantageously
be manufactured from cemented carbide or other wear-resistant materials, while the
intermediate rings 5, 6 may be composed of a softer metal, e.g., steel or cast iron.
However, the material in the different rings is incidental for the realization of
the invention. The essential thing is that the friction joints in the interfaces
between the end surfaces of the rings efficiently prevent slipping between the rings.
For this purpose, the rings have to be held sustainedly compressed by a great spring
force or prestress.
Figs. 2-5 illustrate in detail the nature of a spring device
12 which is built-in into the lock nut 3. In Fig. 2, the spring device is shown
mounted in the lock nut, while Fig. 3 shows only a through hole in which the spring
device is accommodated, and Fig. 4 is an exploded view showing the individual components
of the spring device spaced-apart from each other.
The above-mentioned hole, which extends axially through
the lock nut 3, and which generally is designated 13, includes, on one hand, a front
or inner section 14 that opens in the end surface 7 turned inward of the lock nut
and, on the other hand, a rear section 15, which via a widened countersink 16 opens
in the rear or outward end surface 8 of the lock nut. In the example, the front
hole section 14 has a diameter that is greater than the diameter of the hole section
15, the countersink 16 in turn having a greater diameter than the section 15. The
inner surface of the front hole section 14 is smooth and cylindrical, while the
rear hole section 15 along the entire length thereof is formed with a female thread
The active component of the spring device 12 (see Fig.
4) is a compression spring 18 that acts between a front press body 19 and a rear
stop or support body 20. In the exemplified embodiment, the press body 19 is composed
of a suitably cylindrical pin having a flange 21, against which the front end of
the compression spring 18 may be urged. The support body 20 is in the form of a
piston which, in addition to a cylindrical envelope surface 22, has a suitably planar
back side 23, as well as a front side 24, in which a central seat 25 opens, a rear
end of the press body 19 engaging the seat. A screw 26 may be tightened in the hole
section 15 with the male thread 27 thereof in engagement with the female thread
17. A head 28 of the screw is housed in the countersink 16. A Seeger ring 29 has
the purpose of holding the different spring components in place in the hole 13.
In the shown, preferred embodiment of the invention, the
compression spring 18 is a cup spring that includes a plurality of cups 30, 31,
arranged in a united set. Characteristic of this spring is that a number of first
cups 30 in the set are turned with their small ends pointing in an opposite direction
to the small ends of the other cups 31. More precisely, the cups 30 are placed in
such a way that the small ends point to the left in Fig. 5, while the small ends
of the cups 31 point to the right. In such a way, the two intermediate cups will
have contact with each other along the outer, peripherical edges thereof, while
the two outermost cups are pressed with the internal edges thereof against, on one
hand, the flange 21 of the press body 19 and, on the other hand, the front surface
24 of the piston 20.
The support body 20, the spring 18, the press body 19,
and the Seeger ring 29 are, upon mounting, inserted in proper order in the hole
section 14, while the screw 26 is inserted from behind in the threaded hole section
15. The Seeger ring 19 has only the purpose of holding the spring components 20,
18, 19 in place in the hole section 14.
In the drawings, only one individual spring device 12 is
shown. However, in practice, the lock nut 3 is made with a plurality of peripherical
spring devices which are spaced-apart and arranged in a circular rim formation.
For instance, the lock nut may include eight equidistantly spaced-apart spring devices
along the circumference thereof.
The Function and Advantages of the Invention
When the roll rings 4 and other rings 5, 6 have been applied
to the roll shaft 1, as is shown in Fig. 1, the lock nut 3 is tightened on the male
thread 10. More precisely, the lock nut is tightened by a considerable pressure
against the tightening ring 6. When the lock nut has reached a maximally tightened
end position, the spring devices 12 are activated, more precisely by the fact that
the individual screw 26 is screwed-in a distance in the hole. As a consequence of
the free front end of the press body 19 being urged against the tightening ring
6, the compression spring 18 will then be compressed, more precisely by the fact
that the piston moves in the forward direction in the hole section. When the piston
by way of the screw reaches a position in which the desired spring prestress has
been achieved, the tightening of the screw is terminated. Thereafter the roll is
ready to be taken into operation.
During operation, the different rings of the roll shaft
are exposed to dynamic stresses that in an effective way are carried by the compression
springs in the different spring devices. More precisely, the individual spring forces
are transferred to the common tightening ring 6 in which they are distributed so
that the same will act with an even, high pressure against the adjacent roll ring
4. Because the compression springs in the described way are made in the form of
powerful cup springs, a dynamic spring action is attained and maintained during
long working operations. However, if the spring force eventually is reduced, readjustment
may be effected, viz. by additional tightening of the screws 26 so as to press in
the pistons additionally into the holes. In such a way, the springs are compressed
afresh to the desired degree of prestress.
An important advantage of the roll according to the invention,
and the spring arrangement included therein, is that the spring prestress between
the rings in a simple way may be held reliably high. This in turn guarantees that
the rings do not slip in relation to each other.
Another significant advantage is that the means being necessary
for the spring prestress, do not occupy any part of the roll width, i.e., the available
space between the stop rings 2, 3.
Feasible Modifications of the Invention
The invention is not limited only to the embodiment described
above and shown in the drawings. Thus, it is feasible to arrange the described spring
devices in the fixed stop ring 2 instead of in the lock nut 3. It is even possible
to arrange spring devices in the fixed stop ring as well as the movable lock nut.