Adjustable Truck Tractor Step Assembly for Variable Chassis Layouts

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Solution Overview

Problem

Truck tractor chassis components, such as fluid tanks, vary in position relative to the chassis, necessitating custom body work for each variation, which is inefficient and costly.

Innovation Solution

An adjustable step assembly with a first frame engageable to the chassis, a second frame with a hinge assembly, and a shell that can pivot between open and closed positions, allowing the shell to conform to the body and chassis components, with horizontal and vertical adjustability, and a hinge assembly that allows the second frame to pivot between open and closed positions, enabling the step assembly to adjust to different chassis configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If custom body work is performed for each chassis component variation, then the step assembly can accommodate specific chassis configurations, but manufacturing complexity and cost increase significantly

Engineering Contradiction:

Improveaccommodation of varying chassis component positionsVSAvoidcustom body work requirements

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The step assembly incorporates a movable shell that can pivot between open and closed positions, allowing dynamic adaptation to different chassis configurations. The hinge assembly enables the shell to rotate about a hinge axis, transforming the static body structure into a dynamic one that can accommodate varying component positions without requiring custom body work for each variation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The body is divided into a movable shell portion and a fixed frame portion. The shell can be separated from the frame through the hinge assembly, allowing independent positioning and adjustment. This segmentation enables the shell to be repositioned to accommodate different chassis component locations while the frame remains fixed to the chassis.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If the shell is made fixed to match specific chassis configurations, then manufacturing precision can be improved, but adaptability to different chassis variations is lost

Engineering Contradiction:

Improveshell alignment with chassisVSAvoidflexibility for different chassis component positions

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The shell is made movable rather than fixed, allowing it to be positioned precisely for different chassis configurations. The hinge assembly provides a controlled rotation mechanism that enables the shell to achieve proper alignment with the chassis while maintaining the capability to adapt to various component positions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The step assembly is designed as a universal solution that can accommodate multiple chassis configurations through the movable shell. The same basic assembly with adjustable shell positioning can serve different chassis variations, eliminating the need for custom-built bodies for each specific configuration.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If adjustable mechanisms are added to accommodate chassis variations, then adaptability improves, but device complexity increases

Engineering Contradiction:

Improveadjustability to chassis configurationsVSAvoidhinge and clamp assembly mechanisms

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The hinge assembly provides a relatively simple rotational mechanism compared to more complex adjustable systems. By using a single hinge axis and allowing the shell to pivot, the design achieves adaptability with minimal mechanical complexity, avoiding the need for multiple actuators, motors, or complex linkage systems.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Instead of making the entire body adjustable through complex mechanisms, the invention inverts the approach by making only the shell portion movable while keeping the frame fixed. This simplifies the adjustment mechanism to a single hinge assembly rather than requiring complex adjustment systems throughout the entire body structure.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS20250381915A1Adjustable step assemblies for a truck tractor

Publication Date: 2025.12.18 BUSBY JEFF D

AI summary

A step assembly for a truck tractor of a tractor trailer is designed to accommodate a wide range of chassis designs from different manufacturers while still providing interior access for fuel or diesel exhaust fluid tanks. The step assembly has a first frame attached to the chassis and a second frame supporting the outer shell assembly with step plates. A hinge assembly is adjustably positioned at different (preselected) longitudinal locations along the hinge access and pivotally engages the second frame to the first frame, so the steps are movable between open and closed positions. The hinge assembly can further be vertically adjusted using uprights attached to the first frame. The first frame can further be horizontally adjusted along the chassis using releasable mounting blocks. The invention may provide a paired step assemblies with front and back running boards having similar constructions but sharing a subframe, with independent opening/closing.