Title of Invention

"PNEUMATIC DISC BRAKE SYSTEM FOR LARGE SIZED AC VERTICAL MOTOR"

Abstract

This invention relates to a pneumatic disc brake system for large sized AC vertical motor characterized in that: four pneumatic brake units (C, I), E, F) located 90" apart around a brake disc (5) fixed to brake hub (8) which is fitted on the motor shaft (10), wherein the said brake unit comprises 2 brake pads (1) accommodated in pad-holding shoes (2) and fixed to caliper arms (3), a thruster (A) with a piston slidably fitted within it, a piston rod fixed at one end 1o the said piston and resting at the other end on caliper arm lever of the said brake pushes the said caliper arm levers to actuate the braking action, a control unit (G) to regulate supply of pressurized air to the said brake units comprising an air reservoir (15) connected to air supply line port (A) through check valve (17), the inlet port (P) of a solenoid valve connected to the reservoir through a filter, regulator and lubr.cator (FRL) (20), the outlet port (Q) of the solenoid valve connected to a check valve with choke (13) which is connected to a pressure switch (12), a manometer (18) connected to the said valve (13) through a cut-off cock (11), a terminal box (19) electrically connected to the pressure switch and the 3/2 way solenoid valve.

Full Text

FIELD OF INVENTION This invention relates to a Pneumatic Disc Brake system for large sized AC vertical motor. Large Sized AC vatical motors need to be stopped in a short time for certain applications such as a drive for pumps in power plants. The invention proposes a pneumatic disc brake system which is capable of bringing a large sized AC vertical motor having high inertia to standstill within a short period of time. Such motors need to be stopped in a short period of time, particularly whan running at intermediate speed as otherwise thrust bearing pads of motor bearings may get wiped out due to alienee of formation of oil film in the bearmg pads at that speed. BACKGROUND ART No prior art is known in the field of pneumatic disc brake for large sized AC vertical motor having high inertia. OBJECTS OF INVENTION The objed of invention is to propose a brake system for large sized AC vertical motors. Another object of the invention is to propose a brake system which is suitable for large size AC vertical motors having inertia as high as 3500 Kg m2. Yet another object of the invention is to propose a brake system which works on pneumatic pressure. Further object of the invention is to propose a brake system which can bring a large sized AC vertical motor from 400 rpm to standstill in a period of 7 to 8 seconds. Yet further object of the invention is to propose a brake system which is capable of holding a large sized AC vertical motor in stationary condition against a torque of as high as 10, 000 Nm in opposite direction. STATEMENT OF INVENTION According to this invention there is provided a pneumatic disc brake system for large sized AC vertical characterized in that: four pneumatic brake units located 90° apart around a brake disc fixed to brake hub which is fitted on the motor shaft, wherein the said brake unit comprises 2 brake pads accommodated in pad-holding shoes and fixed to caliper arms, a thruster with a piston slidably fitted within it, a piston rod fbced at one end to the said piston and resting at the other end on caliper arm lever of the said brake pushes the said caliper arm levers to actuate the braking action a control unit to regulate supply of pressurized air to the said brake units comprising an air reservoir connected to air supply line port through check valve, the inlet port of a solenoid valve connected to the reservoir through a filter, regulator and lubricator (FRL), the outlet port of the solenoid valve connected to a check valve with choke which is connected to a pressure switch, a manometer connected to the said valve through a cut-off cock, a terminal box electrically connected to the pressure switch and the 3/2 way solenoid valve. DESCRIPTION OF DRAWINGS LEFT WITH THE PROVISIONAL SPECIFICATION Fig 1. Shows the pneumatic brake system Fig 2. Shows the general mounting arrangement of the pneumatic brake system Fig 3. Shows the assembly of pneumatic brake disc and brake hub Fig 4. Shows the control unit for pneumatic brake system DESCRIPTION WITH REFERENCE TO DRAWINGS The Pneumatic Disc Brake System comprises of 2 brake pads (1) which are accommodated in the Pad-Holding Shoes (2) and are fixed to the Caliper Arms (3). When the pneumatic pressure is applied to the Thruster (4), the piston inside the Thruster pushes apart the caliper arm-levers. This brings the pad-holding shoes closer thereby press against Brake Disc (5). This results in clamping action which introduces the braking moment on the Brake Disc, causing the motor to stop. The brake shoes are self adjusting and ensure equal normal forces from top and bottom side. 4 nos Pneumatic Brake Units (C, D, E, F) are located 90° apart around the Brake Disc and are fixed on the top of the motor housing (6). 2 pairs of diametrically opposite Pneumatic Brake Units are connected through flexible pneumatic piping (7). These are fiirther interconnected to make a single eitfry point for the incoming supply of pressurised air. The Brake Disc (5) is made of non-corrosive steel. It is rigidly fixed to the Brake Hub (8) which is shrunk-fit on the motor shaft (10). Brake Disc (5) and Brake Hub (8) are balanced to the finest possible balancing grade to minimize vibrations. The function of Control Unit (G) is to; (a) regulate the supply of presairised air to the 4 Pneumatic Brake Units when it is switched-on (b) control tht engagement of brake with adjustable pressure increase. (c) control the supply of air pressure during ON-position of brakes. The general layout of various items in the Control Unit is shown in Fig 4 comprises of 1. a Cut-Off Cock (11), 2. a Pressure Switch (12), 3. Check Valve with Choke (13), 4. a 3/2 Way Solenoid Valve (14), 5. a Air Reservoir (15), 6. Mounting Plate (16), 7. a Checl VaIve(17), 8. Manometer (18), 9. Terminal Box (19), 10. FRL Filter, Regulator and Lubricator (20), The control unit functions as follows: From the supply line competed at A, the air under pressure passes through the Check Valve (17) to the Air Reservoir (15) and to 3/2 Way Solenoid Valve (14) at connection P. When the 3/2 Way Solenoid Valve is enerized, the Met Port P opens to the Delivery Port Q, and the air under pressure flows tlsroug Check Valve with Choke (13) to the Brake System. The Check Valve with Choke (13) is used for presmre adjastment. The complete pressure build up takes place within 0.5 seconds. The pressure increase/adjustment is read-off at the Manometer (18). When the brake pressure reaches the desired level, the Pressure Switch (12) operates. The Pressure Switch is also set such that when the Brake is engaged, the operation of motor is not pos^ble. A Cut-oflf Cock (11) has been provided near Manometer (18) to note the actuating air pressure at the Brake. Another Cut Off Cock (11) has been provided at the bottom of the reservoir for drmning of condensate water. Check Valve (17) has be«i provided in the air supply Une to check back flow of pressure from the air reservoir (15) in case of any pressure drop at A on account of break-down of air supply at A. However, in such case, enough pressure remains available in the Air Reservoir (15) for 3 braking operations. When Solenoid Valve (14) is de-energized, the inlet port closes and the delivery line opens to atmosphere at Q, exhausting the actuating pressurised air and thus releasing the brakes. WE CLAIM: 1. A pneumatic disc brake system for large sized AC vertical motor characterized in that: four pneumatic brake units (C, D, E, F) located 90° apart around a brake disc (5) fixed to brake hub (8) which is fitted on the motor shaft (10), wherein the said brake unit comprises 2 brake pads (1) accommodated in pad-holding shoes (2) and fixed to caliper arms (3), a thruster (4) with a piston slidably fitted within it, a piston rod fixed at one end to the said piston and resting at the other end on caliper arm lever of the said brake pushes the said caliper arm levers to actuate the braking action. a control unit (G) to regulate supply of pressurized air to the said brake units comprising an air reservoir (15) connected to air supply line port (A) through check valve (17), the inlet port (P) of a solenoid valve connected to the reservoir through a filter, regulator and lubricator (FRL) (20), the outlet port (Q) of the solenoid valve connected to a check valve with choke (13) which is connected to a pressure switch (12), a manometer (18) connected to the said valve (13) through a cut-off cock (11), a terminal box (19) electrically connected to the pressure switch and the 3/2 way solenoid valve. 2. A brake as claimed in claim 1 wherein the said brake units (C, D, E, F) are fixed on the top of motor housing (6), each of the two pairs of diametrically opposite brake units (D, F), (C, E) connected through flexible pneumatic piping (7). 3. A brake as claimed in claim 1 wherein the said brake hub (8) is shrunk fit on the motor shaft (10). 4. A brake as claimed in claim 1 wherein the brake disc (5) is made of non-corrosive steel with specified mechanical properties. 5. A pneumatic disc brake for large sized AC vertical motor substantially as herein described and illustrated in Fig 1 to 4.

Documents:

619-del-2004-abstract.pdf

619-del-2004-claims.pdf

619-del-2004-complete specification (granted).pdf

619-del-2004-correspondence-others.pdf

619-del-2004-correspondence-po.pdf

619-del-2004-description (complete).pdf

619-del-2004-drawings.pdf

619-del-2004-form-1.pdf

619-del-2004-form-19.pdf

619-del-2004-form-2.pdf

619-del-2004-form-3.pdf

619-del-2004-form-4.pdf

619-del-2004-form-5.pdf

619-del-2004-gpa.pdf

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