US Patent 7677541 Spring structure for bed mattress

Disclosed herein is a spring structure for a bed mattress which comprises a body spring formed in a coil shape, upper and lower end springs wound and extending horizontally at upper and lower portions of the body spring, an exposure wire spring formed integrally with the upper end spring in such a fashion as to be disposed above the upper end spring, and a connection end portion for integrally connecting the upper end spring and the exposure wire spring to each other, wherein a first contact-preventing end 30 is formed at the connection end portion in such a fashion as to be bent inclinedly upwardly from a distal end of the upper end spring positioned outwardly from an uppermost winding of the body spring.