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:
Jul. 06, 1976
Filed:
Oct. 09, 1974
Applicant:
Inventor:
Horst Hegenbart, Schwanheim, DT;
Assignee:
Gebr. Hofmann KG, Darmstadt, DT;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B66B / ;
U.S. Cl.
CPC ...
187 / ; 318 73 ;
Abstract
A lifting apparatus of the type having a number of columns supporting a load platform each column driven by an electrical, polyphase current motor whereby sensors on each column, for example potentiometers, produce a signal indicating the height of that column. The signals are applied to a comparator which in turn provides an output to one or more electronic switches, such as a triac or thyristor having a diode connected in parallel with it for conducting current in an opposite direction, each such switch connected to a winding of a motor to control the current applied so as to reduce any difference in height among the columns.