FIELD OF THE INVENTION
The present invention relates to a system for plate grinding and ,in particular, to a
system for skin grinding of large size plates. Importantly, the system for plate
grinding is very stable and robust to handle severe grinding operations especially for
grinding very large size plates having dimension of even upto 85mm. x 2.1m. x6.5m
and a weight of upto 10 tons. Advantageously, the system incorporates facilities to
carry out dust free grinding by way of sucking the huge amount of grinding dust
generated during the grinding process. The system is thus directed to a fast and
cost- effective grinding of large sized plate with less involvement of manual labour
and is also importantly operator and environment friendly.
BACKGROUND ART
It is well known that grinding is a process for finishing a metal work piece by
removing very little material from its surfaces. An abrasive wheel mounted on the
machine mandrel does the grinding operation, Plate grinding ,in particular, refers to
such grinding of the surfaces of plates. Surface grinders of different sizes and
specifications are available in the machine shop but they have their own limitations
so far as the size of the plate to be ground is concerned.
Usually, such conventional grinding machines are capable of grinding only small
sized plates and thus have serious limitatiOQg for working of large size plates. In
most of the general type surface grinding machines, the table that reciprocate
under the rotating grinding wheel is a very small one with a limited travel length
which involve limitation in using such machines for grinding of large size plates. Also
in case of plate grinding processes ,such as in some steel plants, the plate grinding
process requires not only surface cleaning but also thickness reduction which is
particularly relevant in case of higher thickness plates.
Again, usually such conventional plate grinding machines presently in use do not
have any provision to avoid the environment pollution by way of the dust generated
during the grinding process. Thus the conventional plate grinding machines are
subject to causing environmental pollution as well as operators problems
/complp^ties during grinding since it becomes very difficult to continue the grinding
if the dust and pollution level generated during the process exceeds bearable levels.
OBJECTg 9F THE INVENTION
It is thus the basic object of the present invention to provide for a system of skin
grinding of large size plates which would avoid the afore discussed limitations of
presently available grinding machines and favour grinding large size plates
conveniently and effectively involving less manpower and labour and favouring
improved productivity.
Another object of the present invention is directed to a system for sl*d on and managed effectively even by a single operator to carry out the
entire grinding process thereby making the grinding of large size plate not only
simple and effective but also cost effective.
Yet another object of the present invention is directed to a system for skin grinding
of large size plate which would make the grinding process fast, simple and cost
effective and more importantly and advantageously would favour increasing the
productivity by more than three times in comparison to presently followed manual
grinding involving trolley grinder.
Yet another object of the present invention would favour grinding of large size plate
using a system which would involve less space since unlike the trolley grinding
presently used only one plate is ground at a time.
SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention there is provided a
systern_for£kin grinding of large sized plates comprising:
a movable main car body adapted to be moved along the length of the plate
to be ground kept secured on a stationary bed/platform;
said main car body adapted to carry a cross car along with the grinding head
, a mobile dust suction arrangement , a power pack to activate and position the
grinding wheel with respect to the plate and an operators cabin;
said cross car frame adapted to be moved to and fro across the bed and thus
cover the width of the plate while grinding and operatively linked to said grinding
wheel and its operative system such as to favour up and down motion of the
grinding wheel for the grinding operation with respect to the plate surface;
said dust suction arrangement adapted to arrest flying grinding dust right
from the dust generation point for grinding free of any environment pollution.
The bai^platform for the plate to be ground is provided with means to locate the
plate to be ground and adjustable clamp means for secured support of thepalte for
the grinding operation.
In accordance with a preferred aspect the system for skin grinding of large sized
plates of the invention comprises:
a movable main car body adapted to be moved along the length of the plate
to be ground secured with respect to plate carrying bed/platform;
said main car body adapted to carry a cross car along with the grinding head
, a mobile dust suction arrangement , a hydraulic power pack to activate and
position the grinding wheel with respect to the plate and an operators cabin;
said cross car frame adapted to be moved to and fro across the bed and thus
cover the width of the plate while grinding , a plate with the grinding wheel
mounted thereon along with its drive motor and pulley arrangement being hinged to
said cross car frame, hydraulic means adapted to move said plate hinged to said
cross car frame to favour the grinding wheel operation with respect to the plate
surface;
said dust suction arrangement adapted to arrest flying grinding dust right
from the dust generation point for grinding free of any environment pollution
comprising movable dust collection hood attached to the grinding wheel frame and
arrangement for collection of generated dust in water tank and having desired
flexibility to accommodate the movement of the main car from one end to the other
end.
In the above disclosed system for skin grinding of large sized plates the said main
car body can comprise :
a fabricated structure mounted on four wheels and adapted to run rails laid along
the length of the stationary bed; a drive geared motor adapted to drive the main car
along said rail;
an operative gear arrangement preferably with 1:2 gear ratio transfers adapted to
drive geared motor to an intermediate shaft having brake means preferably an
eldro-barke to stop the machine as and when required;
a chain -sprocket drive arrangement adapted to take the drive at same rate from
the intermediate shaft to main drive shaft located at the fore-end of the machine.
The main drive shaft comprises a combination of shafts joined together with flanged
couplings and supported by bearing boxes, the ends of said shaft operatively
connected to fore-wheels of the car by gears and transfers with rotational speeds
preferably at 1: 2 ratio adapted for linear motion of the car preferably at speed of
about 7.5 m/min.
The car frame structure can comprises rectangular frame structure mounted on
four wheels adapted to move to and fro across the bed and cover the width of the
plate while grinding.
The grinding wheel with drive comprise wheels selected for grinding of plate
preferably of 300mm diameter x 50 thick with 50 mm diameter bore with operative
drive motor.
In accordance with an aspect of the invention a hinged plate adapted to be moved
up and down by means of two hydraulic cylinders hinged to the cross car body,
suitable guide means providing for movement along a guided path.A hydraulic
cylinder for cross travel comprising a hydraulic cylinder hinged to the main car frame
with the piston end hinged to the cross car body adapted to move the cross car
while the grinding wheel is operated for the grinding of the plate. The hydraulic
cylinder for vertical thrust comprising two vertical hydraulic cylinders hinged to the
cross car body with piston end hinged to the hinged base plate adapted to provide
the required thrust for grinding. The hydraulic power pack comprises pumps, valves
and adapted for actuating the hydraulic cylinders.
In accordance with an aspect of the invention the said dust collection system
comprises:
dust collection hood attached to the grinding wheel frame and adapted to move
alongwith the grinding wheel and collect dust right from dust generation point;
flexible dust suction pipe one end of which is connected to the mobile dust collection
hood and the other end is clamped to the dust collection tank, said flexible pipe
preferably suitably supported with respect to poles fixed on main car;
a water tank to hold water preferably upto a level of 1.0 m before overflowing, a "U"
tube operatively connected to the end of flexible pipe dipped into said water with its
top projecting out of the top level of water and exposing to the closed suction zone
such that dust particles which are sucked from the dust generation point fall into
water while cleaner air goes out;
said dust collection hood operatively connected with the suction blower at one side
and the other side connected to the water tank thereby providing for the entire
suction air tight;
said suction blower of selected capacity such as to suck total dust generated during
the plate grinding process and throw dust free air to open atmosphere depositing
heavier dust particles in water tank and very fine dust particles in dust collecting
hood.
The said dust collection hood comprises fabricated cylindrical drum with conical
funnel shaped bottom such that the finer particles of dust carried with air under
suction get collected at the cone shaped bottom.
In accordance with another aspect the operators cabin can comprise a sitting means
and a stand for the operative buttons and levers for operating the car and related
operative mechanism for grinding and positioned to favour viewing of the grinding
operation and car position with respect to the job and the rail.
It would be clearly apparent from the above that the system for skin grinding of the
large plate of the present invention would enable avoiding the drawbacks and
limitations of the manual grinding involving trolley grinder presently in use and
favour providing for a cleaner workplace and an operator and environment friendly
grinding operations.
The system is advantageously adapted to involve very less manpower since it can
be effectively carried out only by one operator who can manage the entire grinding
operation. Also since the system involves less manpower , therefore, the system of
the invention would avoid the complexities of manual grinding which was found to
be very laborious and usually takes very long time with associated productivity
losses.
Advantageously, as apparent from the above system of the invention the same
provides for much desired dust suction arrangements which would arrest the flying
grinding dust which usually cause lot of inconvenience not only to the trolley grinder
operators but also the people in and around the grinding plant complex.
Importantly, such features of the system of the invention are directed to avoid the
limitations of trolley grinder in grinding large size plate and also advantageously
favour avoiding environmental hazards and enable fast and cost effective surface
grinding of large size plate. This would facilitate improving the productivity, which is
found to be more than three times in comparison to be manual grinding presently
applied involving the trolley grinders.
The system is adapted to work in conjunction with the bed which is a fabricated
structure on which the plate to be grounded is mounted such as preferably involving
overhead cranes. Suitable clamping means provide for secured support for the plate
during the grinding operation.
The main car carry the cross car along with the grinding head, the mobile dust
suction hood, the hydraulic power pack and the operator's cabin is basically a
fabricated structure mounted on the four wheels. Operative drive gear motor provide
to drive the main car along a rail laid along the two sides of the bed, the gear
arrang©«*jents, chains pocket drive and a main drive shaft providing to impart to the
car a linear motion for the grinding operations.
The cross car is thus basically comprised a car framed structure such as a fabricated
rectangular frame mounted on four wheels. The frame structure is capable of
moving to and fro across the bed to cover the width of the plate for the grinding
operations. A hinged based plate is hinged to the crossed car frame which has
mounted thereon the grinding wheel along with its drive motor and pulley belt
arrangements. Hydraulic cylinder means are used to provide for cross travel and the
vertical thrusts required for the grinding operations. A power source with a hydraulic
power pack is operatively connected to the hydraulic means for activating the
hydraulic cylinder for the desired cross travel and slash or vertical thrust.
Importantly the system of the invention involves the dust suction arrangement
selectively disposed with respect of the grinding arrangement for collection of the
generated grinding dust right from dust generation point. Moreover, a dust collection
hood arrangement attached to the grinding wheel frame is provided to move along a
grinding wheel and collect the dust right from the dust generation point. A flexible
dust suction pipe is provided to accommodate the movement of the main car from
one end to the other end and in the process favour collection of the generated
grinding dust in a water tank.
It is thus possible involving the above system to carry out skin grinding of large size
plate involving less manpower and fast and cost effectively by way of improved
productivity and ensuring dust and pollution free working area for the operator and
in an around the grinding plant.
The details of the invention, its objects and advantages are explained hereunder In
greater detail in relation to non-limiting exemplary illustration of the system for skin
grinding of large size plates in accordance with the present invention as per the
following accompanying figures :
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
Figure 1 illustrates an embodiment of the plate grinding system arrangement in
accordance with the present invention;
Fugure 2 is a top plan view illustrating the main card with mountings in accordance
with the system of the present invention.
Figure 3 is a sectional illustration of the dust separation unit in accordance with
system of the invention ; and
Figure 4 is a sectional illustration of the dust suction system in accordance with
system of the present invention.
Reference is first invited to accompanying Figure 1 which illustrates in detail the
basic operative constituents of the system for skin grinding of the invention
involving basically the Main car (MC) unit , the Cross Car (CC) unit and the Dust
Suction Unit(DS).AIso as clearly illustrated in the figure are the Hydraulic Power
Pack(HPP),the grinding Wheel (GW), Plate (PL) to be ground and the Bed
/Platform(BD) supporting the Plate (PL) and the Suction Blower with drive (SB).Also
the Hydraulic Hose (HH) and the Hose Support (HS) as part of the hydraulic
actuation system are also shown.
The details of the above constituents in the system and its operative components
are discussed hereunder in greater detail in relation to the accompanying figures 2
to 4.Reference is now invited to accompanying figure 2 which illustrate the provision
of the main car (MC) with mountings in accordance with the invention. As shown in
said figure the system involves the main car (MC) comprising a car body which is
basically a fabricated structure mounted on four wheels (MCW). The car is adapted
to run rails laid along the length of the stationary bed (BD). The stationery bed (BD)
is basically a fabricated structure on which the plate (PL) to be ground is mounted
with the help of over head crane. Preferably, it is provided with pins to locate the
plate (PL) to be ground on horizontal plane and then the plate (PL) is clamped from
sides with some adjustable damps. On eitlier side of tiie bed (BD) along its length are
laid two rails along with the main car (MC) travels during the grinding process.
As further illustrated in said figure the main car (MC) carries with it the cross car (CC)
along with the grinding wheel (GW) head, the mobile dust suction hood (DSH), the
hydraulic power pack (HPP) and the operator's cabin having the Control Panei(CP) . The
car is adapted to travel at the linear speed of 7.5 m/per minute.
A drive geared motor (GM) having capacity of 15 HP, output RPM 20. is provided to
drive the main car (MC) along the two sides of the stationery bed (BD). A gear
arrangement with 1:2 gear ratio is provided to transfer the drive from the drive geared
motor (GM) to an intermediate shaft on which eldro -break has been fitted which helps
in stopping the machine as and when required. A chain - sprocket arrangement (DC)
takes the drive at same rate from the intermediate shaft to main drive shaft located at
the fore-end of the machine.
The drive shaft (DS) of the main car (MC) is basically a combination of shafts joined
together with flanged couplings and supported by bearing boxes. The ends of this shaft
are connected to four wheels (MCW) of the car by gears and transfers the rotational
speed at 1:2 ratio again making the car run at a linear speed of 7.5m./minutes.
The operator's cabin is preferably provided with a chair and a stand having buttons and
levers for operating the car and other mechanism. It is so developed that the operator
can carry out the grinding operations and car position with respect to the job and the
rail.
The cross car (CC) used in the system comprise of a car framed structure (CFS) which
is a fabricated rectangular frame mounted on four wheels (CCW) . It is capable of
moving to and fro across the bed (BD) and thus covers the width of the plate (PL)
while grinding. A hinged base plate is hinged to the cross car frame. The grinding wheel
(GW) along with its drive motors and pulley - belt arrangement (DM & PU) are mounted
on this plate. The plate can be moved up and down with the help of two hydraulic
cylinders hinged to the cross car body. It is provided with suitable guides to favour
movement in a guided path.
The grinding wheel (GW) with drive comprise wheel selected for grinding of the plate
which can be of 300 mnn. diameter x 50 thick with 50 mm. diameter bore. The drive
motor is off 18.5 kw and 2900 RPM. The wheel is driven by V-belt with reduction
ratio of 1:2. Plate grinding can be carried out cross wise i.e. along with width of the
plate.
The cross travel and vertical thrust of the grinding wheel operation is obtained
involving the use of a hydraulic cylinder for cross travel and hydraulic cylinder for
vertical thrust. In particular, the hydraulic cylinder for cross travel can comprise one
hydraulic cylinder of stroke 2.5m. (adjustable depending on the plate width) hinged
with main car frame with the piston end hinged to the cross car body adapted to
move the cross car while the grinding wheel grinds the plate.
The hydraulic cylinder (piston diameter 50mm. stroke 25mm.) for vertical thrust
comprise two vertical hydraulic cylinder hinged to be cross car body with piston end
hinged to be hinged based plate to provide the required thrust for grinding. A power
pack machine (HPP) equipped with hydraulic power pack is provided with required
pump, valve etc. for actuating hydraulic cylinders.
A dust collection unit (DCU) is provided to favour collection of generated grinding
dust (FGD) in water tank and is flexible to accommodate the movement of the main
car from one end to the other end.
The dust collection unit (DCU) basically comprises of dust suction hood (DSH) which
is a rectangular funnel type hood attached to the grinding wheel frame and adapted
to move with the grinding wheel and collect dust right from the dust generation
point. A flexible pipe (FP) one end of which is connected to the mobile dust collection
hood (DSH) while the other end is clamped to the dust collection water tank (WT).
The flexible pipe is suitable supported (hanged) to poles fixed on main car.
The water tank (WT) is preferably a fabricated steel tank (11.7m) long x 1.2m wide
xl.4m high with about) and adapted to hold water upto a level (WL) of nearly 1.0m
before it overflows. One U-tube (UT) connected to the end of flexible pipe is dipped
into the water with its top projecting out of the top level of the water and exposing
to the>:losed suction zone (CSZ) . Dust particle that are sucl