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:
Apr. 14, 1981
Filed:
Jan. 17, 1980
Harold W Stillman, Jr, Clarendon Hills, IL (US);
Sears, Roebuck and Co., Chicago, IL (US);
Abstract
A metal ladder is fabricated from a pair of spaced rails in which the rails have web portions which are provided at spaced intervals with inwardly directed embossments. Each of these embossments has an opening into which one end of a tubular rung is inserted and swaged to the rail. The embossments act as ribs to carry the load toward the flanges constituting the stiffer portions of the rail thereby increasing the strength and effectively reducing the web flexure and angle changes between the rungs and the rails, due to sideward forces in ladder use. By reason of the built in stiffness web thickness may be reduced resulting in savings in materials. Additionally, intermediate these embossments, just described, the web portion of each rail is formed with one or more outwardly directed embossments.