Lifting Apparatus Safety Device with Spring-Loaded Blocking Element

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Solution Overview

Problem

Existing safety devices for lifting gears, such as those in strapping machines, can only block the tool at certain heights and require a person to enter the danger zone to secure it, which is unsafe and inconvenient for maintenance.

Innovation Solution

A safety device using a blocking element that engages with a toothed wheel and toothed rack, where the restoring force holds the blocking element in a locked position, preventing vertical movement when the system is deenergized, allowing the tool to be secured at any vertical position without manual intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a toothed rack portion is inserted to block the tool, then the tool can be secured at any vertical position, but a person must enter the danger zone to secure it

Engineering Contradiction:

Improveability to secure tool at any vertical positionVSAvoidpersonnel safety hazard from entering danger zone

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The safety device automatically activates when the lifting apparatus is deenergized. The blocking element is held against a restoring force in an unblocking position during operation, but automatically returns to the locked position securing the tool at any vertical position without requiring manual intervention.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The blocking element is pre-positioned and spring-loaded to automatically engage the toothed rack when power is removed, blocking the tool before any maintenance personnel would need to enter the danger zone.

Inventive Principle:

Principle #10Preliminary action

2Device complexity

If pawls or bolts are used to block the tool, then the structure is simple, but the tool can only be blocked at certain heights

Engineering Contradiction:

Improvesafety device structure simplicityVSAvoidability to block at any vertical position

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The blocking element functions as a universal blocking mechanism that can engage with the toothed rack at any vertical position along its path, combining the simplicity of a mechanical blocker with the versatility of continuous position coverage.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of discrete blocking points at specific heights, the solution transitions to a continuous blocking capability along the vertical dimension by having the blocking element traverse the full vertical path of the tool, engaging the toothed rack at any position.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of operation

If the blocking element is held against restoring force during operation, then the tool can move vertically freely, but the system requires active energy to maintain this state

Engineering Contradiction:

Improvevertical movement freedom during operationVSAvoidactive energy requirement to hold blocking element

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The blocking element transitions from a static blocked position to a dynamic unblocked position during operation. The restoring force is actively counteracted by the motor-driven toothed wheel mechanism, allowing free vertical movement when needed, while automatically returning to the blocked position when power is removed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The blocking element alternates between two states: blocked during idle/deenergized periods (passive safety state) and unblocked during active operation (movement state). The system periodically transitions between these states based on operational requirements, using the restoring force to maintain the safe default position.

Inventive Principle:

Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The safety device ensures the tool can be secured in any vertical position, facilitating maintenance by automatically locking when the system is deenergized, eliminating the need for personnel to enter the danger zone and providing quick and reliable blocking.

Implementation Method 1

a resilient element (20) in the form of a compression spring...exerts a restoring force on the blocking element (18), said restoring force pushing the blocking element (18) into its locked position

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS9145283B2Lifting apparatus with safety device

Publication Date: 2015.09.29 SPG PACKAGING SYST GMBH

AI summary

A lifting apparatus having a tool, which is vertically displaceable by means of a motor and to which at least a first toothed wheel is coupled in terms of movement. The toothed wheel engages over the vertical path of displacement in a stationary toothed rack. The lifting gear includes a safety device having a blocking element which, in a locked position, stops the tool from moving in the direction of gravity, at least when the lifting apparatus is deenergized, wherein the blocking element stops the tool over the vertical path of displacement, at basically any level in any vertical position, and is held against a restoring force in an unblocking position with vertical movement of the tool, and the restoring force pushes the blocking element into its locked position, at least when the lifting apparatus is deenergized.