FIELD OF THE INVENTION:
The present invention relate to a protecting device. More particularly, the present
invention relates to a bearing protective device mounted on the shaft of bogie rolls
adaptable to heat treatment furnace hearth to resist damage caused by thermal energy.
BACKGROUND OF THE INVENTION:
There is no standard bearing available in the market which can be able to resist
internally high thermal expansion of furnace roll shaft. In the existing system, a set
screw type ball bearing unit is used. The bearing unit is directly mounted on the roll
shaft with a clearance fit against the recommended fit for rotating inner ring load. The
set screw which is fixed in the inner race of the bearing, slides along the key way of the
roll shaft depending upon the thermal expansion. The set screw engaged in the key
way also rotates the inner race with the shaft. This bearing assembled fails prematurely
due to its low rating and deviation from recommended fit. It also damages the roll shaft

and the key way which needs to reburfished time to time to reuse by
undercutting weld deposit and machining operation.
A further existing arrangement provided with a double row spherical
roller bearing with recommended fits. However, in this arrangement
the bearing is mounted on the roll shaft with a adaptor sleeve, while
the outer race is fettled in a sleeve. This sleeve slides in the bore of
the bearing housing for taking up thermal expansion. This
arrangement has the disadvantage of high axial load which is taken by
one row of spherical rollers and may cause high temperature and
premature failure of bearing while usage in the heat-treatment
furnace.
To overcome such adversity in the existing system an emphasized is
made to develop a special device to protect the bearing and to prevent
wrapage of bearing of rolls of bogie caused by the influence of high
thermal energy during it's long stay at heat treatment furnace.

OBJECTS OP THE INVENTION:
It is therefore, an object of the present invention relates to propose a
bearing protecting device mounted on a shaft of bogie rolls adaptable
to heat-treatment furnace hearth to resist damage caused by Thermal
energy which eliminates the disadvantages of Prior Art,
Another object of the present invention is to propose a bearing
protecting device mounted on a shaft of bogie rolls adaptable to heat-
treatment furnace hearth to resist damage caused by Thermal energy
which reduces the break-down hours of the furnace.
A further object of the present invention is to propose a bearing
protecting device mounted on a shaft of bogie rolls adaptable to heat-
treatment furnace hearth to resist damage caused by Thermal energy
which increases the life time of a standard bearing.
A still further object of the present invention is to propose a bearing
protecting device mounted on a shaft of bogie rolls adaptable to heat-

treatment furnace hearth to resist damage caused by thermal energy
which increases the productivity.
A yet further object of the present invention is to propose a bearing
protecting device mounted on a shaft of bogie rolls adaptable to heat-
treatment furnace hearth to resist damage caused by Thermal energy
which is handy and easy to fit on the rolls.
SUMMARY OF THE INVENTION
A novel idea has been developed using sliding of roll shaft through a
protecting sleeve fitted in inner race of the bearing with inbuild
lubrication feature of sliding surface and the keyways. The Thermal
expansion of the rotating furnace hearth roll is allowed to take place
through a hollow sleeve. The hollow sleeve is fitted with clearance
/sliding fit onto the roll shaft with two sliding keyways at 180 degree
apart The hollow sleeve is radially and axially supported on a
standard double row spherical roller bearing mounted on a bearing
housing at free end with standard recommended fits for rotating inner

ring load specified by bearing manufacturer. This arrangement fulfils
the requirement, supporting the roll shaft as well as taking up Thermal
expansion independently. There is also inbuilt lubrication provision
for the roll shaft sliding area including the keyways.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING:
Fig - 1 shows a schematic diagram of water cooled furnace roll
having assembled with protecting sleeve at far side i.e.
non-drive side.
Fig - 2 shows a schematic diagram of protecting sleeve amounted on
the shaft and bearing mounting over the sleeve at the non-
drive side.
Fig - 3 shows a schematic diagram of end view of water cooled
furnace rolls of Fig 1.
Fig - 4 shows a schematic diagram of bearing housing of Fig - 6.
Fig - 5 shows a schematic diagram of retainer of Fig - 6.
Fig - 6 shows a schematic diagram of protective sleeve of Fig - 1
and 6.

Fig - 7 shows a schematic diagram of salvaged roll end (Non-drive
side).
Fig-8 shows a schematic diagram of Locking key of Fig 1 and 6.
Fig - 9 shows a schematic diagram of spacer.
DETAILS DESCRIPTION OF A PREFERRED EMBODIMENT
OF THE INVENTION:
According to the present invention as shown in Fig - 6 a bearing
protecting device (9) marked as 'sleeve' comprising of a cylindrical
hollow part made of steel material having a outside collar (20) at outer
surface near rear end (21) to the device (9) is provided with a
plurality of key slots disposed at 180° apart in the inner face
throughout the length. The dimension of the inner diameter of the
device (9) is such that it will accommodate the outer diameter of the
shaft rolls (1). The outer surface of the device (9) have a slide
smaller diameters at both end part (21, 22) than that of the central
part (24). The device is further provided with a under cut (25)

through out the outer surface for oiling. The length of the device is such that it will
cover the length wise dimension of bearing housing (13), spherical roller bearing (14),
spacer (12) and bearing housing cover (15). The outer diameter of the device is such
that it will accommodate the inner diameter of lower race (16) of the spherical bearing
(14). Both the inner surface and outer surface of the device (9) are highly machine
finished. One side end of the lower race (16) of the bearing (14) is fastened at the
collar part of the device (9) and the other side end of the lower race (16) is fastened
with a spacer (12). For mounting the sleeve device (9) with the shaft rolls, the existing
shaft is machined to reduce the diameter to match with the inner diameter of sleeve
device (9) and making a plurality of key way slots (18,18) of the shaft at 180 degree
apart to match the keyway (19,19) of the sleeve device (9). A plurality of keys (2) of
steel material are prepared separately consisting of a plurality of holes for each key,
through which a hex. socket head cap screws can be inserted in each hole and can be
fastened with the shaft.

For assembly, first of all a key (2) is fitted at the respective each key
slot (18) of the shaft (1) by means of a plurality of screws (3) in each
key (1). The sleeve device (9) is inserted into shaft through key way
(19) of sleeve device (9) tightly. The lower race (16) of the bearing
(14) is inserted over the sleeve (9) till it reaches the collar (20) of the
sleeve (9). A spacer (12) is inserted over the sleeve device (9) and
fixed the position of the bearing (14). A bearing housing (13) and a
bearing housing (13) cover are fitted over the bearing (14).

WE CLAIM
1. A bearing protecting device (9) mounted on the shaft of bogie rolls adaptable to
heat treatment furnace hearth comprising:
a hollow cylindrical part (9) having a collar (20) at outer surface near front end
(21) and having a smaller diameter at both ends (21,22) than that of central part
(24) at the outer surface;
a plurality of key slots (19,19) provided on the inner surface of cylindrical part
(9) along the length disposed at 180 degrees apart;
a under cut provided on the outer surface of the cylinder part (9) for oiling and
controlling expansion;
characterised in that,
the inner diameter of the cylindrical part (9) accommodates the outer diameter
of the shaft roll (1) and the outer diameter of the cylindrical part (9) is
accommodated by the inner diameter of the lower race (16) of the bearing (14)
when a plurality of keys (2) are fastened with the key way slots (18,18) of the
roll (1) by means of screws (3) through which matched key slot (19) of the
cylindrical part (9) is inserted and fixed.

2. A bearing protecting device (9) as claimed in claim 1, wherein the inner surface
and outer surface of the device (9) are highly machined.
3. A bearing protecting device (9) as claimed in claim 1, wherein the hollow
cylindrical part is made of steel.
4. A bearing protecting device (9) as claimed in claim 1, wherein the keys (2) are
made of steel, hardened by proper heat treatment.
5. A bearing protecting device (9) as claimed in claim 1, wherein a spacer (12) is
inserted over the sleeve device (9) for fixing the position of the bearing (14).
6. A bearing protecting device (9) as claimed in claim 1, wherein the outer diameter
of the bearing (14) is accommodated by the inner diameter of the bearing
housing cover (15).
7. A bearing protecting device (9) as claimed in claim 1, wherein the length of the
device is equal to the length wise dimension of bearing housing (13), spherical
roller bearing (14), spacer (12) and bearing housing cover (15).

8. A bearing protecting device (9) as claimed in claim 1, wherein hex. socket head
cap screws are employed to fasten the keys (2) in the slots (18,18) of the shaft
role (1).

A bearing protecting device consists of a collar (20) at outer surface near front end
(21), having a smaller diameter at both ends (21,22) than that of central part (24) at
the outer surface. Two key slots (19,19) are provided on the inner surface of cylindrical
part (9) along the length disposed at 180 degrees apart. An undercut is provided on the
outer surface of the cylinder part (9) for oiling and controlling the expansion. The inner
diameter of the device (9) accommodated the outer diameter of the shaft roll (1) and
the outer diameter of the cylindrical part (9) is accommodated by the inner diameter of
the lower race (16) of the bearing (14) and the outer diameter of the bearing (14) is
accommodated by the inner diameter of the bearing housing cover (15) when two keys
(2) are fastened with the roll (1) by means of hex socket head cap screws (3) through
which matched key slots (19,19) of the cylindrical part (9) are inserted and fixed.