Spring brake chamber ALS Mk-3 : construction and working 

The spring brake chamber ALS Mk-3 is a actuator of the air brake system of ALS. It help to apply the service brake operating by pressurized air into the vehicle's rear wheel. Spring brake chamber is two types first one is single diaphragm type and second one is double diaphragm type. The ALS vehicle have double diaphragm type spring brake chamber. 


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Construction of spring brake chamber ALS Mk-3 :-

Spring brake chamber ALS Mk-3 have two air chamber namely primary chamber and secondary chamber. Both chamber have a seperate diaphragm primary diaphragm and secondary diaphragm. 

For making strength to the rubber diaphragm both have aluminum disc. To keep in initial position of both diaphragm there have seperate returning spring also.

The spring brake chamber AlS Mk-3 have two air inlet. One air inlet for service brake or foot brake, which is connected with secondary air chamber. Second air inlet for hand brake or parking brake which is connected with primary air chamber.

Spring brake chamber ALS Mk-3

The spring brake chamber have a air continuity channel which connected with primary and secondary air chamber for making easy movement of the diaphragm.

There is a push rod into the secondary air chamber which is connected with secondary diaphragm from one side and same as from other side the push rod is connected with fork and the fork is connected with slack adjuster. 

Working of spring brake chamber ALS Mk-3 :-

The spring brake chamber ALS Mk-3 have two working functions, first one is service / foot brake action and second one is hand / parking brake action.

1. Service brake action of spring brake chamber ALS Mk-3 :-

When driver apply some amount of pressure on the foot brake pedal then pressurized air enter into the secondary air chamber and push the secondary diaphragm. 

Secondary diaphragm moves forward and the secondary diaphragm is connected with push rod so push rod also moves forward. The push rod is connected with fork and slack adjuster so fork moves forward and the slack adjuster rotate clockwise. 

Spring brake chamber ALS Mk-3

The slack adjuster is connected with 'S' type cam with help of the cross shaft that's why the 'S' type cam change from vertical manner to horizontal manner and push the brake shoe, and finally brake shoes cought the brake drum. The service brake applied into the vehicle.


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2. Parking brake action of spring brake chamber ALS Mk-3 :-

When driver put the hand brake lever at on position. This action will cut off the air supply to the primary air chamber of the spring brake chamber and the spring of primary diaphragm push the diaphragm forward. The primary diaphragm have a plunger. This plunger push the secondary diaphragm. 

For moving forward of secondary diaphragm the action happens same as service brake. The parking brake applied into the vehicle. 

But think is that the service brake is applied by supplying the air pressure and the parking brake is applied by releasing air from spring brake chamber.


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