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. 20, 1979
Filed:
May. 09, 1977
Jerry E Johnson, Bellevue, WA (US);
Ryan Instruments, Inc., Kirkland, WA (US);
Abstract
A portable strip chart recorder is provided with a constant speed strip chart advancing drive powered from a clockworks and gear drive unit. The gear drive unit is sealed from the strip chart so that it cannot be tampered with when the strip chart is changed. The constant speed drive comprises a constant speed sprocket spool which engages sprocket holes in a strip chart running between a feed spool and a take-up spool. The feed spool is provided with a drag to allow variations in the rotational speed of the strip chart on the spool and provide tension on the chart whereas the take-up spool is provided with a slip clutch that allows the chart to be wrapped at a constant tangential speed even though the diameter of the chart on the take-up spool varies.