Drawbar Safety Locking and Immobilization Mechanism

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Solution Overview

Problem

Existing drawbars with movable rods for coupling vehicles face safety issues due to rod displacement in case of cylinder failure, causing jolts and potential damage, and lack of immobilization when not in use, especially with longer drawbars that can hit the ground on potholes or bumps.

Innovation Solution

A drawbar with a safety device that automatically locks the movable rod in case of cylinder failure and an immobilization mechanism that raises the coupling end when not in use, using a locking assembly and immobilizer elements to prevent movement and ground contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the drawbar is made movable to allow coupling and uncoupling operations, then the ease of operation is improved, but the reliability deteriorates due to potential failure of the cylinder and uncontrolled movement of the rod

Engineering Contradiction:
Improveease of coupling and uncouplingVSAvoidsafety against cylinder failure
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The locking device is designed to automatically engage and lock the rod in position when the cylinder fails or loses pressure, preventing uncontrolled movement before it can cause damage. The locking mechanism with spring-loaded locking elements is pre-positioned to catch the rod if it moves unexpectedly.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The locking device acts as a safety backup that is already in place and ready to prevent harmful effects of cylinder failure. The spring-loaded locking elements are prepared to engage with the rod's locking surfaces, providing a cushioning effect against sudden uncontrolled movements.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Adaptability or versatility

If the drawbar is made movable to allow adjustment of vehicle distance, then the adaptability is improved, but the stability deteriorates due to lateral and vertical swinging when not locked

Engineering Contradiction:
Improveadjustment of vehicle distanceVSAvoidstability when not locked
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The immobilization device is designed to automatically engage when the rod is in a specific position, preventing lateral and vertical swinging before it can cause damage. The locking elements are pre-positioned to catch and stabilize the drawbar when not in use.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If the drawbar has a great length to extend from the front axle, then the adaptability is improved for various coupling configurations, but the harmful factors increase due to risk of hitting the ground on potholes or speed bumps

Engineering Contradiction:
Improvecoupling configuration flexibilityVSAvoidrisk of ground contact damage
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The immobilization device prevents the drawbar from moving downward to hit the ground by engaging locking elements that physically block the movement path. This preliminary anti-action counteracts the harmful effect of ground contact before it can occur.

Inventive Principle:
Principle #9Preliminary anti-action

4Ease of operation

If the locking device is made automatic to operate without energy, then the ease of operation is improved, but the device complexity increases

Engineering Contradiction:
Improveautomatic locking operationVSAvoidcomplexity of locking mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The locking device is designed to be self-actuating, using the rod's own movement and spring-loaded elements to automatically engage and lock without requiring external energy or complex control systems. The mechanism serves itself by utilizing the mechanical energy already present in the system.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3638519B1Drawbar with safety mechanism and latching in position
Publication Date: 2021.05.05 LOHR IND
  • EP3638519B1 patent drawingFigure 1~2
  • EP3638519B1 patent drawingFigure 3~4
  • EP3638519B1 patent drawingFigure 5~6

AI summary

The drawbar (1) comprises a main cylinder (14) with a moving rod (15) equipped with a coupling ring (13) for coupling same to a second vehicle (5). The drawbar (1) comprises a latching device (16) with safety ratchet (19) which is automatically activated by latching in the event of failure of said main cylinder (14), in order to prevent the exit of the moving rod (15). The drawbar (1) is mounted to pivot with respect to the road vehicle (2) to which it is fitted and further comprises an immobilisation device (32) provided to prevent any pivoting of the drawbar (1) when the movable rod (15) of said drawbar (1) is in the retracted position.