Hoist with overload safety protection

US4698565A · kind A · utility

Assignee

• Mannesmann AG · DE

Inventors

• Klaus Behnke · Schriesheim, DE
• Anton Munzenbrock · Dortmund, DE

Key dates

• Filing date: Jul 18, 1985
• Grant date: Oct 6, 1987
• Expiry date: Jul 18, 2005

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S388/912
• WIPO field: Handling
• WIPO sector: Mechanical engineering

Abstract

The hoist, lifting apparatus or the like of our invention comprises at least one hoist motor, a protective controller for the hoist motor, and an overload safety device operating on the protective controller, wherein the overload safety device has a cable load force pick-up with a tension measuring bridge, an analyzer, and a mechanism for suppression of load peaks in periodic load fluctuations. The tension measuring bridge is connected with two connecting conductors to a bridge supply generator and has two output conductors for transmission of the output signal of the tension measuring bridge. The analyzer acts on the protective controller for the hoist motor. Between the analyzer and the tension measuring bridge is a frequency converter with associated frequency generator which changes the output signal of the measuring bridge into a periodic signal. The analyzer has at least one counter with an adjustable initial state, at least one analyzer controller and a frequency divider, which produces a periodic control signal as a gate pulse for the counter from a reference frequency of normal frequency. With the counter during the gate pulse the cycles are countable, which includes the p…