The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 03, 1987
Filed:
Aug. 27, 1985
Thomas J Wells, Carthage, MO (US);
Angelo Serafini, East Boston, MA (US);
Leggett & Platt, Incorporated, Carthage, MO (US);
Abstract
A bedding foundation box spring having novel double twist coil springs interconnecting a wooden base frame and a top wire grid. The coil springs each comprise a single length of wire having a middle section located in a diametral plane of one end convolution of the spring and a pair of spring arms coiled in the same rotational direction from opposite ends of the middle section. Each of the spring arms is formed into a helix of varying pitch which terminates in a free end of the spring arm. The free ends of the two spring arms of each coil are located on opposite sides of the end convolution of the coil and are secured to the wire grid. The novel coils are manufactured by inserting a straight length of wire through a stationary pair of forming dies and a mandrel located between the dies. With the middle of the straight length of wire located in the mandrel, the mandrel is then simultaneously rotated and moved axially while the ends of the length of wire are pulled through the stationary forming dies.