Delivery Van Differential Lock for Curb Obstacle Traction
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Solution Overview
Problem
Existing delivery vehicles face difficulties in overcoming road obstacles such as curbs without significant physical effort, particularly when approaching at an angle, due to the design of differentials and traction belts, which can lead to one wheel spinning freely and preventing forward motion.
Innovation Solution
A differential lock mechanism is implemented with a bridge element to lock the drive wheels together, ensuring simultaneous torque application, allowing the vehicle to overcome obstacles even with imprecise approaches by coupling the drive axles via a bridge shaft and coupling units with toothed connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a differential is used to compensate for speed differences between drive wheels, then the vehicle can navigate turns and uneven surfaces, but the differential causes one wheel to spin freely when one wheel loses contact with the ground, preventing obstacle overcoming
Solution Approach 1:
The patent extracts the locking function from the differential mechanism by introducing a separate differential lock device. This lock can engage the drive axles directly through a bridge element, bypassing the differential's speed-differencing action when obstacle overcoming is required, while leaving the differential functional for normal driving conditions.
Solution Approach 2:
The system dynamically switches between two operational modes: normal differential operation for turns and uneven surfaces, and locked differential operation for obstacle overcoming. The coupling units enable this dynamic transition, connecting drive axles to the bridge element only when needed for obstacle negotiation.
2Reliability
If a differential lock is engaged with a dead man's brake, then the vehicle can be held stationary, but the vehicle cannot move forward when the brake is engaged
Solution Approach 1:
The braking and differential locking functions are segmented into separate systems. The dead man's brake acts only on the wheels independently, while the differential lock connects the drive axles through the bridge element. This segmentation allows the brake to hold the vehicle stationary without preventing the differential lock from engaging the drive axles for forward motion.
Solution Approach 2:
The bridge element acts as an intermediary that connects the drive axles directly, providing a mechanical pathway for torque transmission that bypasses the brake's holding action on the wheels. This intermediary connection enables the vehicle to overcome the brake's stationary holding when obstacle negotiation is required.
3Reliability
If coupling units with toothed connections are used to engage drive axles, then synchronized wheel rotation is achieved, but the complexity of the coupling mechanism increases
Solution Approach 1:
The toothed coupling units are designed to engage automatically when the bridge element is positioned correctly relative to the drive axles. The geometry of the teeth and receiving grooves enables self-alignment and self-engagement, reducing the need for complex control mechanisms while ensuring reliable synchronized rotation.
Data Source
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AI summary
Delivery van (1), in particular postal delivery van, comprising: a chassis (2) on which at least two drive wheels (3), preferably two rear wheels (3a), are arranged, a drive motor (8) for driving drive axles (7) of the drive wheels (3), a differential for compensating for speed differences between the drive wheels (3), a superstructure (5) carried by the chassis (2) for receiving goods, in particular mail items, and a differential lock (9) for locking the differential for the drive wheels (3).