Pivoting Forklift Seat Backrest for Impact Attenuation
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Solution Overview
Problem
Materials handling vehicle seats with fixed backrests are uncomfortable for operators due to the pounding action caused by driving over irregular surfaces, leading to early fatigue, and there is a need for a simple, cost-effective solution that protects operators from pinching and prevents damage to elastomeric pads.
Innovation Solution
A seat backrest with a compressive member that biases it into an upright position, allowing it to pivot relative to the seat base upon force application, attenuating forces and providing improved comfort and visibility for operators, while a backrest stop limits excessive deformation and protects the pad.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed backrest is used to firmly support the operator, then operator support is improved, but operator comfort deteriorates when driving over irregular surfaces due to pounding action
Solution Approach 1:
The backrest is designed to pivot dynamically relative to the seat base through a compressive member mechanism, allowing it to move from a fixed position to an angled position when force is applied by the operator or during vehicle operation over irregular surfaces, thereby resolving the contradiction between firm support and comfort
2Ease of operation
If a pivoting backrest mechanism is added to improve comfort, then operator comfort is improved, but device complexity increases
Solution Approach 1:
The compressive member changes its compression parameter dynamically - remaining compressed to maintain the backrest in an angled comfortable position, and decompressing to return the backrest to upright position, providing pivoting functionality through parameter change rather than complex mechanical linkages
Solution Approach 2:
The compressive member automatically performs the work of returning the backrest to its neutral upright position after the operator releases it, eliminating the need for additional springs, dampers, or motorized mechanisms that would increase complexity
3Ease of operation
If the backrest pivots freely to attenuate forces, then operator comfort is improved, but the compressive member may suffer damage from excessive force application
Solution Approach 1:
The compressive member is pre-compressed between the backrest and seat base before any pivoting action occurs, creating a cushioning effect that absorbs excessive forces and prevents damage to the member while still allowing controlled pivoting motion for comfort
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 pivoting seat backrest effectively reduces operator discomfort and fatigue by absorbing forces from surface irregularities, maintaining comfort and extending the life of the elastomeric pad.
Implementation Method 1
a compressive member which, in a neutral configuration, biases the seat backrest to a predetermined position from which the seat backrest pivots upon application of force to the backrest sufficient to deform the compressive member from the neutral configuration
Implementation Method 2
the resiliently biased backrest attenuates forces that are transferred to the backs of operators occupying the seats when the vehicles are driven over commonly occurring irregularities in surfaces on which the vehicles are driven
Data Source
AI summary
A compressive member is used to bias a seat backrest into a predetermined position, generally upright as illustrated, relative to a seat base with the compressive member deforming to enable the seat to be pivoted by the application of force to the backrest. When used on a materials handling vehicle for which it is particularly applicable, the resiliently biased backrest attenuates forces that are transferred to the back of an operator occupying the seat when the vehicle is driven over irregularities in a floor supporting the vehicle.