FIELD OF INVENTION
The present invention relates to an improved system for producing steel arch section. More
particularly, the invention relates to an improved system for producing steel arch section
comprising tilting means and roller entry guide means adapted for smooth entry in the roller
stands with the elimination of cobble generation and minimizing operational delays. The
invention also relates to a process for production of the arch section adopting the system.
BACKGROUND AND PRIOR ART
Generally, blooms made in the ingot route are charged in the re-heating furnace for heating
the blooms at 1300°C. Then the heated blooms are fed in the roughing stand where the bloom
blank is made. Thereafter the blooms are fed into the first stand and converted to nearly
elliptical shaped profile. This elliptical shaped stock is then tilted vertically manually with the
help of torque and then fed into the second stand through friction type entry guide. The bar is
then finished into the final steel arch section through successive six stands.
The first drawback in tilting is because of the manual operation. In fact it is not possible for
the conventional system to hold the bar vertically with stability and there would always be a
tendency to fall or tilt in either side of the bar. This ultimately enhances the probability of
knocking the bar at the end of friction entry guide.
The second limitation is with the friction entry guide. The friction entry guide is made from 2
inch thick mild steel plate without any divergence at the back. Moreover, the clearance
between the material entering in the second stand and left and right hand rollers of the guide
has to be kept nominal. Tolerance between the left and right hand guide space of the second
stand is kept very nominal (3mm approximately). Because of the tilting tendency at the
vertical position, the bar got jammed often creating all sorts of operation delay, high cobble
generation and low yield. All these leads to low production per campaign of steel arch
section.
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GB338175 describes an improvement relating to foot attachments for pit props or steel arches
employed as colliery or mining roof supports. The props as described comprises one or more
shear members of U-section bolted at one end to a foot-piece or a cap of H-section steel and
at the other end the shear members have a thin transverse web which is torn by the said prop
or arch connecting bolts when relative movement occurs between the prop and the foot-piece
or cap under excessive load.
EP0092307 describes an improved support arches for colliery tunnels wherein the tunnel
support arch is formed from I-section or channel section material and divided into a crown
portion and leg portion. The invention prevents sudden fracture of the joint between crown
and legs and in the case of bolt holes in the slice plates where an area of reduced strength
extends from each bolt hole additional warning is given of joint failure.
JP6200625 describes a method of arch truss construction for producing frame to efficiently
frame large heavy machine. The frame comprises plurality of divided trusses interconnected
to each other in a vertical turnable manner.
JP63013616 describes a straightening method and device for camber of flat steel. The yield is
improved by rolling the flat steel in longitudinal direction more strongly as a part is more
inside from the center line of the flat steel arch deformed by width cutting and more weakly
as a part is more outside from the center line. Cylindrical straightening roll and conical
straightening roll are installed for rolling the flat steel.
JP2002371674 describes a construction method for arch shaped and curved roof comprising
framing of a steel frame truss having upper and lower chords and a diagonal member between
column materials, placing and mounting the corrugated roofing panel on the upper chord,
tensioning of a cable after being passed through the lower chord, so that the corrugated
roofing panel placed on the upper chord can be raised in an arch shaped manner in the
directional orthogonal to the direction of continuous corrugation.
3

GB816728 describes a sectional roof supporting arch comprising bell shaped trough section
end strapped between a stilt comprising two similar sections forming a downwardly tapering
space into which the end of the arch can sink under load.
In none of the documents described above an improved system and process for producing
steel arch section with the elimination of cobble generation and minimizing operational
delays are found.
Thus there is need to provide for an improved system and a process involving a tilting means
and roller entry guide means for smooth entry in the roller stands with the elimination of
cobble generation and minimizing operational delays to produce steel arch section.
OBJECTS OF INVENTION
Thus the basic object of the present invention is an improved system for producing arch
section providing smooth entry of the bar of the arch section in the pass thus improving
productivity.
Another object of the present invention is to provide better stability to the bar in vertical
position.
Another object of the present invention is to provide a process for improved production of
steel arch with the minimization of off centering of the bar in the roller guide.
The other object is to eliminate cobble generation during entry of the bar in the pass.
SUMMARY OF INVENTION
Thus according to the basic aspect of the present invention there is provide an improved
system for producing steel arch section, wherein said system comprises :
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(i) tilting means adapted to tilt bar coming out from first pass in a predetermined
vertical position providing better stability to the bar, said titling means
comprising tapered plate operatively provided on transfer carriages of the system
forming a compartment having predetermined projections such that the bar is held
vertically; and
(ii) roller guide means in functional co-operation with said tilting means so as to
receive the bar after vertical tilting such that there is no off centering of said bar,
said roller guide means comprises funneled apertures having predetermined angle
of divergence providing smooth entry of the bar.
According to another aspect of the present invention there is provided a process for producing
steel arch section, wherein said process comprises an improved tilting process and an entry
process;
wherein said tilting process comprises holding the bar coming out from the first pass in a
predetermined vertical position providing better stability to the bar in its tilted position and
wherein said entry process comprises shifting of the bar to second pass adapting roller guide
wherein said roller guide provides smooth entry of the input bar providing centering of the
bar during feeding the bar inside the roller guide.
DETAILED DESCRIPTION OF INVENTION
The system of the present invention comprises tilting means having a taper plate operatively
provided on the rope transfer carriages forming a compartment (pocket) with projection
means (herein described as skid finger) where the stock/input bar is held in vertical position
only. Another series of skid fingers made of mild steel is operatively fixed in a straight line
on the floor plate itself.
The roller guide means in functional co-operation with said tilting means of the system of the
present invention comprises pick up surface having tongue like profile with funneling ranging
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from 50 mm to 15 mm. The above profile of the pick up surface provides diverging aperture
with predetermined angle at the entry end thus enabling smooth entry of the bar. As the
operator is at a remote place from the entry point, so it is not possible to feed the bar exactly
in the pass. In case entry guide without sufficient divergence very often the bar knocks at the
end of the bar and cobble will take place. The predetermined divergence at the entry point of
the roller guide for pass 2 nullifies the problem of off centering of the bar during feeding the
bar inside the guide. The said divergence ranges from 15° to 30°. Thus the bar is placed in the
guide and move forward and is centered automatically due to desired positioning of profiled
rollers which are aligned with the pass 2. The profiles of rollers are configured identical to
the profile of the input material providing proper gripping of the bar in position.
The front end of the bar is thus gripped by the rollers of the entry guide such that there is a
predetermined line contact between the rollers and guide thus reducing frictional force
existing between the input bar and the roller entry guide. The frictional force depends on the
surface contact area, the more the surface of contact, the more is the frictional force. In the
present invention line contact provide minimum frictional force leading to the reduction in
the cobble generation. Pass 1 to 4 are grooved in the rolls housed in the second stand and the
required guides entry as well as delivery ( 4nos. for 4 different passes) are put on the same
cramp bar in both the side of the stand. So, the entry roller guide i.e. the feeding guide, is
designed in such a way that the same can be put on the cramp bar along with other guides. A
plate (herein described as locking plate) having thickness ranging from 1 to 1.5 inch with
drilled holes at a predetermined distance is adapted such that the distance is more than the
width of the cramp bar. Drilled holes are also provided across the height of the left as well as
right side wall of the guide at a distance matching with the locking plate. Plurality of long
bolts are fitted in the holes and the plate is adapted to form a groove inside which the cramp
bar passes and the guide is tightened with the cramp bar by tightening the nuts.
In the process of the present invention the blooms made in the ingot route is charged in the
re-heating furnace for the heating the blooms at 1300°C. Then the heated blooms are fed into
the roughing stand (herein described as pass 1) for making bloom blank. The bloom blank
having shape of nearly elliptical shaped stock from the pass I is tilted by the improved tilting
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process which comprises of mechanized tilting system adapted to hold the bar i.e. the
stock/input bar in a predetermined vertical position with better stability in the pocket made on
the carriage of rope transfer system.
In the process of tilting the bar in the vertical position before feeding it into the stand 2, at
first the near elliptical shaped bar coming out of pass 1 is shifted to fixed finger welded on
the floor plate by rope transfer. Then the bar is pressed against the fixed finger and tilting is
started on the taper plate. At the instant when the taper is about to cross the fixed finger, the
bar is dropped down in the pocket vertically on the rope transfer carriages. The bar is then
shifted to pass 2 and is fed in the said pass through the guide means comprising roller entry
guide.
The tilted bar is then fed through modified entry process with the introduction of roller guide
means.
BRIEF DESCRIPTION OF ACCOMPANYING FIGURES
Figure 1 illustrates a conventional entry guide.
Figure 2a and 2b illustrate the process of tilting of the bar in the present invention.
Figure 3 illustrates a schematic diagram for entry roller guide in the present invention.
Figure 4 illustrates a plan view of the roller guide in the present invention.
Figure 5 illustrates a flow chart of the process of the present invention.
DETAIL DESCRIPTION OF ACCOMPANYING FIGURES
In figures 2a and 2b the process of tilting the bar is illustrated. The vertical tilting of the bar
can be realized from the figures. The bar (43) is pressed against the fixed finger (21) and
tilting is started on the taper plate (22).
In figure 3 schematic diagram for entry roller guide means of the present invention is
illustrated. Top roll (31)and bottom roll (32) has a predetermined clearance (33)in between.
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The guide roll (41) being operatively located such that the median of the clearance travels
exactly through the space provided between the roll guides (41).
In figure 4 the guide roll (41) is profiled with its inner surface (42) identical to the shape to
the input bar (43).
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WE CLAIM
1. An improved system for producing steel arch section, wherein said system comprises:
(i) tilting means adapted to tilt bar coming out from first pass in a predetermined
vertical position providing better stability to the bar, said titling means
comprising tapered plate operatively provided on rope transfer carriages of the
system forming a compartment having predetermined projections such that the
bar is held vertically; and
(ii) roller guide means in functional co-operation with said tilting means so as to
receive the bar after vertical tilting such that there is no off centering of said bar,
said roller guide means comprises funneled apertures having predetermined angle
of divergence providing smooth entry of the bar.
2. System as claimed in claim 1, wherein the tilting means comprises plurality of
projections operatively fixed in a straight line on the floor plate in a manner that near
elliptical shaped bar coming out of pass 1 is shifted to the projections such that tilting
is started at the tapered plate so as to drop the bar vertically down in the compartment.
3. System as claimed in claim 1, wherein the diverging aperture is adapted to provide
smooth entry of the bar minimizing cobble generation.
4. System as claimed in claim 1, wherein the roller guide has funneling ranging from 50
mm to 75 mm.
5. System as claimed in claims 1 to 4, wherein the diverging aperture has angle of
divergence ranging from 15° to 30°.
6. System as claimed in claims 1 to 5, wherein the roller guide comprises rollers adapted
to grip the front end of the bar such that predetermined line contact is maintained
between the rollers and guide so as to reduce frictional force between the input bar
and the roller entry guide thereby reducing cobble generation.
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7. A process for producing steel arch section, wherein said process comprises an
improved tilting process and an entry process;
wherein said tilting process comprises holding the bar coming out from the first pass
in a predetermined vertical position providing better stability to the bar in its tilted
position and
wherein said entry process comprises shifting of the bar to second pass adapting roller
guide wherein said roller guide provides smooth entry of the input bar providing
centering of the bar during feeding the bar inside the roller guide.
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8. An improved system and a process for producing steel arch section as herein
described and illustrated with reference to the accompanying figures.

An improved system for producing steel arch section comprises tilting means adapted to till
bar (43) coming out from first pass in a predetermined vertical position providing better
stability to the bar (43), said titling means comprising tapered plate (22) operatively provided
on transfer carriages of the system and roller guide means (31, 32, 41) in functional co-
operation with said tilting means so as to receive the bar (43) after vertical tilting such that
there is no off centering of said bar (43). A process for producing steel arch section comprises
tilting process which holds the bar coming out from the first pass in a predetermined vertical
position providing better stability to the bar in its tilted position and entry process which
shifts the bar to second pass adapting roller guide wherein said roller guide provides smooth
entry of the input bar providing centering of the bar during feeding the bar inside the roller
guide.