Pivoting Seat Backrest With Compressive Member For Operator Fatigue Reduction
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Solution Overview
Problem
Materials handling vehicle seats with fixed backrests are uncomfortable for operators due to bouncing and rotation caused by driving over irregular surfaces, leading to early fatigue, and there is a need for a simple, cost-effective pivoting mechanism that protects operators from pinching and prevents elastomeric pad damage.
Innovation Solution
A compressive member, made of resilient materials like silicone or Santoprene, biases the seat backrest into an upright position and allows it to pivot relative to the seat base upon force application, attenuating forces and providing improved comfort and visibility during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
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 bouncing and rotation
Solution Approach 1:
The backrest is designed to pivot dynamically relative to the seat base through a compressive member mechanism, allowing it to adapt to vehicle motion and surface irregularities while maintaining operator support. The backrest can tilt forward and backward within controlled limits, transforming the static fixed structure into a dynamic adaptive one.
Solution Approach 2:
The compressive member changes its compression state based on applied forces, allowing the backrest to pivot when force exceeds a threshold. This parameter-based control enables the backrest to remain stable during normal operation but pivot to attenuate impacts from bumps and irregularities.
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 pivoting mechanism is segmented into discrete components: the backrest, seat base, compressive member, and protective structure. This modular segmentation simplifies assembly, maintenance, and manufacturing while enabling the complex pivoting function through simple individual elements working together.
Solution Approach 2:
The compressive member acts as an intermediary element between the backrest and seat base, providing the pivoting function through its compression and relaxation. This single intermediary component enables the entire pivoting mechanism without requiring complex linkages or actuators.
3Ease of operation
If the backrest is made resilient to attenuate forces, then operator comfort is improved, but the protective function against pinching deteriorates
Solution Approach 1:
The protective structure is positioned beforehand to cushion and protect against pinching hazards. It acts as a first line of defense that prevents operator appendages from reaching the pivoting mechanism, thereby eliminating the pinching risk before it can occur.
Solution Approach 2:
The protective structure serves as an intermediary barrier between the operator and the pivoting mechanism. It physically blocks access to the compressive member and pivot point, preventing direct contact that could cause pinching while allowing the pivoting function to operate freely behind the barrier.
4Ease of operation
If elastomeric pads are used for pivoting, then operator comfort is improved, but durability deteriorates due to excessive force application
Solution Approach 1:
The protective structure performs preliminary anti-action by preventing excessive force application to the elastomeric pad before damage can occur. It limits the maximum force that can be applied to the compressive member, thereby protecting the pad from forces that would exceed its design limits and cause premature failure.
Solution Approach 2:
The protective structure cushions against excessive forces before they can damage the elastomeric pad. By physically limiting the range of motion and force application, it prevents scenarios where operators could inadvertently apply damaging forces to the pad.
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 shocks from surface irregularities, while a protective structure prevents damage and pinching, enhancing both comfort and durability.
Implementation Method 1
the compressive member deforming to enable the seat backrest to be pivoted relative to the seat base by the application of an appropriate force to the backrest
Implementation Method 2
A compressive member is associated with the structure and the seat backrest. The compressive member, in a neutral configuration, biases the seat backrest to a predetermined position from which the seat backrest pivots relative to the seat base upon application of force to the seat backrest sufficient to deform the compressive member
Data Source
Figure 1
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AI summary
A compressive member (140) is used to bias a seat backrest (132) into a predetermined position, generally upright as illustrated, relative to a seat base (128) 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 (100) for which it is particularly applicable, the resiliently biased backrest attenuates forces that are transferred to the back of an operator occupying the seat (124) when the vehicle is driven over irregularities in a floor supporting the vehicle.