Transfer Case Locking Mechanism for Vehicle Immobilization
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Solution Overview
Problem
Conventional sewer cleaner trucks rely on hand brake systems for immobilization during operation, which limits gearbox functionality and does not allow independent locking of the vehicle in a working position without engaging the rear wheels.
Innovation Solution
A mechanism comprising a first, second, and third pinion assembly within a sealed housing, controlled pneumatically to lock the primary output shaft in rotation, enabling independent immobilization of the vehicle while allowing gearbox operation, using a third pinion that translates between inactive and active positions to engage with both the first and second pinions, and maintained by spring-loaded pushers and O-rings for tightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If handbrakes attached to rear wheels are used for immobilization, then the vehicle can be locked in position, but the gearbox cannot operate to supply the equipment
Solution Approach 1:
The invention separates the immobilization function from the rear wheel handbrake system by introducing an independent locking mechanism that acts on the primary output shaft of the transfer case. This segmentation allows the vehicle to be immobilized through the transfer case locking mechanism while the gearbox remains free to operate and supply power to the equipment, thus resolving the contradiction between reliable immobilization and gearbox operation capability
Solution Approach 2:
The patent introduces the transfer case as an intermediary component between the gearbox and the rear wheels. By placing the locking mechanism at the transfer case level rather than at the wheel level, it creates an intermediate control point that can immobilize the vehicle's drive system while leaving the gearbox input free to receive power and transmit it to the equipment through the secondary output shaft
2Reliability
If the primary output shaft is locked to prevent vehicle movement, then the vehicle cannot move unintentionally, but the gearbox cannot transmit power to the equipment
Solution Approach 1:
The locking mechanism is designed to be dynamic and selective, capable of engaging or disengaging the lock on the primary output shaft as needed. During equipment operation, the lock is disengaged to allow power transmission through the transfer case to the equipment. When vehicle movement is a concern, the lock can be engaged to prevent unintentional movement. This dynamic control resolves the contradiction between vehicle stability and power transmission capability
Solution Approach 2:
The invention applies locking action locally at specific points in the transfer case mechanism rather than globally throughout the entire drivetrain. The locking mechanism targets only the primary output shaft when needed, while leaving the secondary output shaft and its connection to the equipment free to rotate and transmit power. This localized approach allows simultaneous achievement of vehicle stability and power transmission
3Adaptability or versatility
If a locking mechanism is added to the transfer case, then independent immobilization is achieved, but the device complexity increases
Solution Approach 1:
The locking mechanism is merged with the existing transfer case structure, utilizing the transfer case housing and existing shafts as integral components of the locking system. The locking pin or pawl is integrated into the transfer case case, and the spring mechanism is housed within the transfer case. This merging approach achieves independent immobilization capability while minimizing the increase in device complexity by reusing existing structural elements rather than adding completely separate systems
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
Enables secure immobilization of the vehicle during operation without relying on rear wheel hand brakes, allowing continuous gearbox operation and preventing untimely movement, with a pneumatic control system ensuring precise positioning and a detection mechanism for operator confirmation.
Implementation Method 1
pneumatic control means designed to cause the third pinion to move from its inactive position to its active position
Implementation Method 2
indexing means such as at least one spring-loaded pusher attached to the external cylinder and designed to be engaged as appropriate in one or the other of the annular grooves
Implementation Method 3
The edges of the outer face and the lateral areas of the inner face of the third gable are fitted with O-rings, contributing to the sealing of said housing
Data Source
Figure 1~3
Figure 4~5
AI summary
The present invention relates to a device (1) for immobilizing a vehicle, particularly a vacuum truck, in its working position. This device is equipped with at least one working attachment connected to a transfer case (2) having at least one input shaft (3) mechanically connected to the vehicle's gearbox, one primary output shaft (4) mechanically connected to the vehicle's rear axle, and at least one secondary output shaft mechanically connected to the working attachment. The device also relates to means for mechanically connecting said input shaft (3) to said primary output shaft (4) in a "traveling" state of said vehicle, or to said secondary output shaft in a working state of said vehicle. The device is characterized in that it comprises a mechanism designed and intended to prevent rotation of said primary output shaft (4) in said working state of said vehicle.