Specification for double action floor springs (without oil check) heavy door
1974 Edition

According to Clause 4.1 and Table 1 of IS 7197, components of the floor spring are made from specified materials: The foundation main body can be brass sheet (minimum 1.25 mm thickness, CuZn 40 alloy per IS:410-1967), mild steel sheet (minimum 1.25 mm per IS:226-1969), cast iron (Grade 20 per IS:210-1970), aluminium die-castings (minimum 2 mm thickness, A-5M or A-6M per IS:617-1959), aluminium alloy sheets (minimum 1.25 mm, NS4-1/4H or HS20-W per IS:737-1965), or zinc base alloy die-castings (minimum 2 mm, Alloy 1 or 2 per IS:742-1966). The spring rod is made of mild steel (IS:226-1969). The governing pivot uses mild steel that is case hardened (Grade 1 per IS:2708-1964) or malleable cast iron (IS:2108-1952). The top cover can be cast brass (Grade 3 per IS:292-1961), brass sheet (minimum 1.25 mm, CuZn 40 per IS:410-1967), aluminium die-castings (minimum 2 mm, A-5M or A-6M per IS:617-1959), or aluminium alloy sheets (minimum 2 mm, NS4-1/4H or HS20-W per IS:737-1965). Springs are made of spring steel Grade 1 (IS:4454-1967). The shoe component may be cast brass (Grade 3 per IS:292-1961), mild steel, or cast iron (Grade 20 per IS:210-1970).

Per IS 7197, the maximum permissible weight for each leaf of a heavy door operated by the floor spring is 125 kilograms. The standard ensures that the floor spring is designed and tested to handle this weight. Additionally, the force required to open a door leaf weighing up to 125 kg through a 90-degree angle at one meter from the frame should not exceed 2 kilograms-force (20 Newtons).

Performance testing as per IS 7197 involves selecting samples according to Appendix A and mounting the floor spring on a door leaf weighing 125 kg. The door leaf is then cycled through 50,000 opening and closing operations at a rate of 6 to 8 cycles per minute, moving through an angle of 180 degrees each time. The test is conducted under normal environmental conditions. Upon completion, the floor spring must exhibit no signs of damage or decline in functionality to pass.

Yes, IS 7197 specifies corrosion protection treatments: For mild steel and cast iron parts, all dents, burrs, and sharp edges must be removed, followed by pickling to eliminate grease, rust, and scale. After pickling, phosphating is applied as per IS:3618-1966, followed by a primer coat such as red oxide. Putty (IS:426-1961) may be used for filling surface imperfections. Aluminium parts require anodizing with a coating thickness not less than Grade AC 10 according to IS:1868-1968.

The manufacturer is required to supply necessary accessories including adjusting steel bars and any other components essential for installation and fine adjustment, such as adjusting screws. Clear and detailed instructions for correct fixing and installation of the floor spring must be provided. Packaging should protect the product and include labeling with the manufacturer's name or trademark, quantity, country of origin, and year of manufacture. The shoe is designed to fit the governing pivot via a square profile to maintain horizontal alignment, and adjustment screws allow for precise positioning of the door leaf when closed.