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:
Jan. 18, 1977
Filed:
Apr. 03, 1975
Terry R Downing, Hazel Crest, IL (US);
Allis-Chalmers Corporation, Milwaukee, WI (US);
Abstract
An overload protective system continuousy monitors the forward overturning moment on a counterbalanced lift truck and prevents further raising of the carriage or further forward tilting of the mast when the tilting moment is excessive. A strain gage sensor connected in an electrical bridge derives a strain signal proportional to the mechanical strain in a load carrying anchor pin for the tilt jack which resists the forward overturning moment acting on the truck; a differential amplifier raises the level of the strain signal; a comparator which receives the output of the differential amplifier derives a trip signal when the strain signal reaches a predetermined magnitude; a shift register receiving clock pulses from an oscillator as a time reference records the history of the comparator output and a decoder analyzes the shift register output and sets a latch when the trip signal comparator output has been present for a predetermined interval of time; and disabling means responsive to setting of the latch de-energize operating coils for blocking valves which inhibit further raising of the carriage or further forward tilting of the mast.