Forestry Winch Pulley Closure Flap Design

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Solution Overview

Problem

Forestry winches experience rope disengagement and tearing due to the rope not winding in a straight manner, leading to potential damage, and existing safety mechanisms protrude from the housing, causing deformation and suboptimal operation.

Innovation Solution

A pulley with a closure flap and locking pin system, where the closure flap is movably attached via a bolt and can be locked using a pin, allowing for easy installation and preventing rope derailing by covering the sheave, with a design that ensures no elements protrude from the housing during operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pin with stem, spring and restrictor is used to control the closure flap, then the safety mechanism can prevent rope disengagement, but the protruding stem deforms and the mechanism ceases to operate optimally

Engineering Contradiction:

Improvesafety mechanism operationVSAvoiddeformation of protruding elements

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The harmful protruding stem with spring and restrictor is completely removed from the design. The invention replaces this complex protruding mechanism with a simple pin that operates entirely within the housing, eliminating the source of deformation and operational failure.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of having the control mechanism protrude outward to operate the closure flap, the invention inverts the approach by having the pin operate from within the housing. The pin engages with the closure flap through internal openings, reversing the traditional outward-protruding design.

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of operation

If the closure flap is made movable for fast rope installation, then ease of operation is improved, but the rope may derail without proper safety coverage

Engineering Contradiction:

Improverope installation speedVSAvoidrope containment

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The closure flap is pre-positioned to cover the sheave opening before rope installation begins. This preliminary coverage ensures that once the rope is installed and the flap is secured with the pin, the rope is immediately contained and cannot derail during operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The closure flap is designed as a movable component that can be easily opened for rope installation and then securely locked in the closed position. This dynamic design allows the flap to transition between open and closed states, facilitating easy operation while ensuring reliable containment when closed.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP3912951A1A pulley with a closure flap and a winch with the said pulley

Publication Date: 2021.11.24 PISEK - VITLI KRPAN D O O

Figure 1~2

AI summary

The invention belongs to the field of forestry winches, more precisely to the field of constructional details in winches, which are related to pulling a load by winding the rope onto a drum via a pulley. The invention relates to a pulley with a closure flap (1) and a winch with the said pulley. The pulley comprising at least: - a housing (O), inside which a freely rotatable sheave for leading a rope is installed in an axis, - a closure flap (1) installed via a bolt (2) of the pulley, which allows movement of the pulley when it is installed on a winch, or via a hinge on the housing of the pulley, wherein the closure flap has an open position and a closed position, and switching between both positions is enabled with a locking pin (3).