Walk-behind Tiller Parking Brake Pin-and-Groove Locking Mechanism
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Solution Overview
Problem
Conventional walk-behind tillers fail to securely lock the movement of traveling wheels on sloping or inclined farm fields due to the friction-based drum-type parking brake mechanism, which is ineffective in such conditions.
Innovation Solution
A walk-behind tiller design featuring a main clutch on/off device and a parking brake on/off device with an engaging member that stops the rotation of the driving shaft, ensuring secure locking without slipping, and an operating handle configuration that prevents accidental operation of the parking brake.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a drum-type friction brake is used for the parking brake mechanism, then the structure is simple, but the braking reliability is insufficient on slopes or inclined fields
Solution Approach 1:
The patent replaces the drum-type friction brake mechanism with a pin-and-groove mechanical locking mechanism. The parking brake pin directly engages with the driving shaft through a groove, creating a positive mechanical lock that prevents rotation without relying on friction. This substitution fundamentally improves reliability on slopes while maintaining structural simplicity.
Solution Approach 2:
The invention changes the fundamental operating principle of the brake mechanism from friction-based (continuous contact) to geometric-based (discrete engagement). The groove shape and pin geometry are designed to provide reliable locking under gravitational loads on inclined surfaces, transforming the parameter of braking action from force-dependent to geometry-dependent.
2Ease of operation
If the parking brake on/off device is positioned near the operating handle for easy access, then the ease of operation is improved, but the risk of accidental operation increases
Solution Approach 1:
The parking brake on/off device is positioned on the transmission case body, which is a different spatial plane and location relative to the operating handle. This dimensional separation in the control layout allows the operator to easily reach the brake control while physically distancing it from the main operating handle, reducing the probability of simultaneous or accidental activation of both controls.
3Strength
If the parking brake is not disengaged before operation, then the transmission mechanism is protected from damage, but the loss of time occurs due to forgetful disengagement
Solution Approach 1:
The system performs preliminary action by automatically disengaging the parking brake through the clutch operation sequence. When the main clutch is engaged, the clutch operating mechanism simultaneously actuates the parking brake release mechanism, ensuring the brake is disengaged before power transmission begins. This eliminates the need for manual brake disengagement and prevents forgetful operation.
Solution Approach 2:
The clutch operating mechanism provides feedback control for the parking brake state. The engagement of the main clutch triggers the brake release sequence, and the system monitors the clutch state to ensure proper brake disengagement. This feedback loop ensures the transmission mechanism is protected while eliminating manual intervention and associated time loss.
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 effectively locks the traveling wheels on slopes or inclined fields, preventing unintended movement and protecting the transmission mechanism, while ensuring easy operation and preventing forgetful disengagement of the parking brake.
Implementation Method 1
since the conventional parking brake device is a brake mechanism of the drum type, the resistance is applied to the rotation of the traveling wheels by the frictional force occurring in a brake shoe
Data Source
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AI summary
A tiller (100) includes traveling wheels (4L and 4R), plural tilling claws (6), an engine (15), and a transmission case (2), and the tiller includes a main clutch lever (18) which switches connection and disconnection of transmission of the driving power, a driving shaft of traveling system (40), whose one end part (41) protrudes from the transmission case, the one end part (41)being provided with a parking brake groove (41 a), and a parking brake lever (311) which has a parking brake pin (301) being engageable with the parking brake groove (41 a) of the driving shaft, and which is capable of stopping and releasing of the driving shaft (40), wherein by operating the parking brake lever (311) to stop the rotation of the driving shaft, the parking brake pin (301) is engaged with the parking brake groove (41 a), so that the rotation of the driving shaft (40) is stopped.