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@article{206730,
        author = {Ghanshyam Pawar and Akshay Thakre and Nikhil Darokar},
        title = {Effect of a Variable Radius Cam Shaft on Brake Shoe Engagement Sequence in Cable-Operated Drum Brakes: An Experimental Study Using Dial Gauge Measurements},
        journal = {International Journal of Innovative Research in Technology},
        year = {2026},
        volume = {13},
        number = {2},
        pages = {2702-2708},
        issn = {2349-6002},
        url = {https://ijirt.org/article?manuscript=206730},
        abstract = {This paper examines a simple design change to the cam shaft of a cable-operated drum brake enlarging the contact-face corner radius on the leading shoe side while retaining the standard radius on the trailing shoe side and quantifies its effect on brake shoe engagement using direct dial gauge measurements. Two cam shafts were tested on the same drum brake assembly: a Constant Radius Cam (CRC) with all four corner radii equal at 2 mm, and a Variable Radius Cam (VRC) with 4 mm corners on the leading side and 2 mm corners on the trailing side. Dial gauges mounted on both shoes recorded radial expansion at 5 mm increments of cam lever travel, from the free position (120 mm) to full application (85 mm).
With the CRC, both shoes expanded together: the trailing-to-leading expansion difference remained within ±0.02 mm over the full stroke, indicating engagement that is simultaneous within the resolution of the measurement. With the VRC, the leading shoe lifted markedly more slowly at 5 mm of stroke it had expanded 0.073 mm against 0.190 mm for the trailing shoe, a trailing-to-leading ratio of 2.60 so the de-energized trailing shoe contacts the drum first at every stroke position. The three nominally identical 2 mm faces (CRC leading, CRC trailing, and VRC trailing) produced closely matching lift curves, agreeing within 0.005 mm at first contact, which serves as an internal consistency check on the measurement. The study measured engagement kinematics only; acoustic noise was not measured, and the implications for brake noise are inferred from the measured engagement sequence together with mechanisms established in the literature. The full data set, the mechanism, and practical design guidance are presented.},
        keywords = {},
        month = {July},
        }