Parking Lock Pre-Selection Mechanism for Work Machines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing parking lock systems for work machine power trains are complex and prone to interference from external contaminants and misalignment, particularly when the work machine is on a hill, requiring continuous operator effort and increased complexity.
Innovation Solution
A simplified parking lock pre-selection mechanism using a system of interconnected links and a spring to yieldably urge the links into an elongated state, with a stop limiting the length to initiate engagement of the parking lock pawl with the output shaft teeth, reducing sensitivity to contaminants and eliminating the need for continuous operator input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a telescoping spring loaded link is used in the parking lock actuation system, then the parking lock can be actuated, but the clearances in the telescoping link are prone to sticking or interference from external contaminants
Solution Approach 1:
The single telescoping link is segmented into two separate links (first link and second link) that are pivotally connected. This segmentation eliminates the internal clearances of a telescoping design while maintaining the spring-loaded actuation function, thereby preventing sticking and contaminant interference.
Solution Approach 2:
A pivotal connection point acts as an intermediary between the first and second links, replacing the telescoping clearance mechanism. This pivotal intermediary provides a reliable connection that is less sensitive to contaminants while still allowing the necessary movement for parking lock actuation.
2Ease of operation
If a telescoping link is used for parking lock actuation, then the mechanism can function, but the link can be misaligned when the work machine is on a hill, translating weight into force against the link
Solution Approach 1:
Dividing the link into two segments connected by a pivotal joint allows each segment to independently accommodate alignment variations. The pivotal connection enables the mechanism to adapt to tilted positions without transmitting excessive force, reducing misalignment issues when the machine is on a hill.
Solution Approach 2:
The pivotal connection changes the mechanical parameters of the link assembly, allowing rotational movement that accommodates alignment variations. This parameter change enables the system to adapt to different orientations and reduce the transmission of gravitational force to the link during tilted operation.
3Device complexity
If a solid link is used between the operator lever and parking lock pawl, then the mechanism is simple, but if the shaft alignment causes the pawl to engage the top of a tooth, the operator must move the work machine to permit engagement
Solution Approach 1:
The spring-loaded link assembly performs preliminary action by pre-positioning the parking lock pawl near the engagement position. This preliminary positioning reduces the travel required and allows the operator to initiate engagement without needing to move the entire work machine, as the spring mechanism compensates for minor misalignments.
Solution Approach 2:
Replacing the rigid solid link with a dynamic spring-loaded link assembly allows the system to adapt during operation. The spring mechanism provides dynamic adjustment capability, enabling the pawl to engage teeth even when there are slight alignment variations, eliminating the need to move the work machine.
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 provides a robust and reliable pre-selection mechanism that simplifies the parking lock process, reduces sensitivity to environmental contaminants, and minimizes frictional forces, allowing for effective locking without continuous operator effort.
Implementation Method 1
A spring is interconnected between the first and second link to yieldably urge them to an elongated state
Data Source
AI summary
A parking lock pre-selection mechanism for a work machine is disclosed in which a pawl is engageable with teeth on a power train output shaft to lock it in place. An operator lever is used to preselect the parking lock position. The mechanism includes first and second pivotally interconnected links, urged by a spring to a maximum length set by a stop. The spring causes the pawl to be urged into place when the teeth and pawl are in proper alignment.