Compact Telescoping Lift Arms With Nested Locking Geometry

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Solution Overview

Problem

Existing telescoping lift arms in vehicle lifts face limitations in extension and retraction due to friction and cantilever loading, leading to restricted lift arm lengths and potential deformation under high forces, while angular position adjustments are cumbersome and prone to strain.

Innovation Solution

The design incorporates compact telescoping arms with nested sections and a rotatable lock mechanism, featuring a rotatable and rotationally fixed gear system with a lock pin and abutment members to secure angular positions and limit strain, enabling smooth operation and extended range of motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If telescoping lift arm sections are extended to provide variety of lengths, then adaptability to different vehicle sizes is improved, but friction between adjacent sections increases and prevents further changes in length

Engineering Contradiction:
Improveadaptability to different vehicle sizesVSAvoidease of adjusting lift arm length
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent employs nested telescoping sections where inner arm sections are received within outer arm sections, allowing multiple length configurations while maintaining a compact structure. The nesting arrangement enables the sections to extend and retract smoothly with reduced friction compared to side-by-side configurations.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The lock pin mechanism provides dynamic locking that engages only when needed to maintain position, rather than continuous friction. The spring-loaded lock pin automatically engages with notches on the telescoping sections to hold the arms at desired lengths, eliminating the need for constant friction-based retention.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If lift arm sections are made shorter to reduce friction, then ease of telescoping is improved, but the cantilever load capacity and strength are reduced

Engineering Contradiction:
Improveease of telescoping motionVSAvoidcantilever load capacity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The lift arm is divided into multiple telescoping sections (outer, middle, inner) that can independently extend and retract. This segmentation allows each section to be optimized for its specific function while collectively providing the necessary strength and telescoping capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lock pin mechanism preliminarily locks the telescoping sections at desired positions before loading occurs. By establishing the correct length configuration in advance, the system ensures optimal load distribution and structural strength when the vehicle weight is applied.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If a fixed lock member with short circumference is used to lock the lift arm angle, then the locking mechanism is compact, but pivot forces are concentrated in small areas causing strain

Engineering Contradiction:
Improvecompactness of locking mechanismVSAvoidstress concentration on lock members
Core Design Contradiction:
Device complexityVSStress or pressure

Solution Approach 1:

The lock pin is configured to engage with notches distributed along the circumference of the telescoping sections rather than relying on a short circumferential lock member. This dimensional change distributes the locking force across multiple engagement points, reducing stress concentration while maintaining mechanism compactness.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The spring-loaded lock pin acts as an intermediary that translates the locking requirement into distributed notch engagement. The spring mechanism allows the lock pin to flex and distribute forces evenly across multiple notches, preventing stress concentration on any single point.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Device complexity

If manual adjustment of lift arm angle is required, then simplicity of the locking mechanism is improved, but time and effort required for positioning are increased

Engineering Contradiction:
Improvesimplicity of locking mechanismVSAvoidtime for angular positioning
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The spring-loaded lock pin mechanism is self-actuating through the natural telescoping motion of the arm sections. As the sections extend or retract, the lock pin automatically engages or disengages from notches, eliminating the need for manual intervention to lock the position while maintaining mechanical simplicity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The manual operation of continuously adjusting and locking the arm angle is replaced by an automatic notch-based locking system. The mechanical system uses the motion itself to trigger the locking action, substituting manual locking operations with an automated mechanical response.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution allows for secure, efficient, and extended telescoping motion of lift arms, reducing strain on lock pins and enhancing the lift's versatility and safety by allowing precise angular adjustments and limiting deformation.

Implementation Method 1

a pressurized fluid cylinder connected between the lift carriage and the post, such as a hydraulic cylinder

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

friction between adjacent telescoping sections typically prevents changes in the lengths of the lift arms

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4139242B1Two post vehicle lift with compact telescoping arms
Publication Date: 2025.12.03 BENDPAK INC
  • EP4139242B1 patent drawingFigure 1
  • EP4139242B1 patent drawingFigure 2
  • EP4139242B1 patent drawingFigure 3

AI summary

A compact telescoping lift arm assembly includes an outer arm section pivotally connected by a pivot member to a lift carriage vertically slidable on a post and an inner arm section telescopically received within the outer arm section and movable in and out of the outer arm section. The inner arm section has a nesting slot formed at an inner end thereof to nest about the pivot member when the inner arm section is retracted into the outer arm section.