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IP.com Disclosure Number: IPCOM000241099D
Publication Date: 2015-Mar-26
Document File: 1 page(s) / 120K

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The IP.com Prior Art Database

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The drum brakes work on the principle of curved shoes (pad material) bonded or riveted on a shoe which is equivalent of the pad materials in a rotor brake system.The normal operation of drum brakes require them to be curved and put as angle of arc. It is in the usual operation of drum brakes that the radius of the shoes is uniform. The normal operation of the drum brake requires contact at the end of the shoes (Heel to Toe contact). When the brake is applied, the shoe moves and presses the lining against the inside of the drum. The friction between lining and drum Frequently however, heel and toe contacts result in squeal or grind/graunch type of noise. To eliminate the unwanted noise, the radius of the shoes is ground in a way to provide more radius at the center of the shoe and a lower radius at the edges. This revised radius shape allows for a more solid contact at the middle of the shoe. This aspect is clearly depicted in the diagram (b) in the following the diagram which represents fall off grinding vs. (a) which is normal grinding. It can be seen from the diagram(a) that the normal grinding operation has same radius of 5.6mm across the shoe. For the diagram(b) we have a fall-off grinding where the radius is high in the middle (6.0mm) and reduces at the end of the shoes. It has been found by physical testing that the fall off grinding helps in reducing the grind noise.

a)Normal grinding

b) Fall off grinding Conclusions...