Hydraulic Latching Device for Refuse Tipper Carts
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Solution Overview
Problem
Existing refuse cart tippers with mechanical linkage systems are prone to damage from obstructions and fail to accommodate varying sizes and positions of refuse carts, limiting their adaptability and operational range.
Innovation Solution
A latching device utilizing a master cylinder in fluid communication with a slave cylinder, where a roller attached to a rod follows a cam plate to synchronize latch motion with tipper movement, and a counterbalance valve directs excess fluid pressure to an accumulator, preventing damage and ensuring secure attachment of refuse carts across different configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical linkage is used to operate the latch, then the latch can be actuated through mechanical connection, but the system is prone to damage when obstructions are present in the latch path
Solution Approach 1:
The patent replaces the mechanical linkage system with a hydraulic system. A master cylinder receives hydraulic fluid through a flexible hose, and a slave cylinder attached to the latch converts hydraulic pressure into mechanical motion to actuate the latch. This substitution eliminates the mechanical linkage that was vulnerable to obstructions, while maintaining the ability to reliably actuate the latch through hydraulic actuation.
2Adaptability or versatility
If mechanical linkage with fixed range of motion is used, then the latch can be operated within a specific range, but the system cannot adapt to varying refuse cart sizes and positions
Solution Approach 1:
The patent introduces dynamic adjustability to the latch system through a cam mechanism with an adjustable cam profile. The cam profile can be modified to change the range of motion and timing of the latch actuation, allowing the system to adapt to varying refuse cart configurations. This dynamic adjustment capability enables the same hydraulic system to accommodate different cart sizes and positions without requiring complex reconfiguration of the entire linkage system.
3Reliability
If the latch is designed with fixed timing and range of motion, then the manufacturing is simplified, but the system fails when the lower bar position varies outside the configured range
Solution Approach 1:
The patent employs a cam mechanism with an adjustable cam profile that can be modified to accommodate varying lower bar positions on different refuse carts. The cam profile's geometry can be adjusted to change the timing and range of motion of the latch actuation, ensuring reliable hooking across a broad range of cart configurations. This dynamic adaptability maintains high reliability while accommodating position variations that would otherwise cause failure.
Solution Approach 2:
The patent changes the geometric parameters of the cam profile to adapt the latch system to different refuse cart configurations. By modifying parameters such as cam radius, eccentricity, and timing angles, the system can accommodate varying lower bar positions while maintaining reliable latch actuation. This parameter adjustment approach enables the system to adapt to different cart types without redesigning the entire latch mechanism.
4Object-affected harmful factors
If hydraulic fluid pressure is allowed to build up due to obstruction, then the latch can be forced to move, but the counterbalance valve protects the system by directing excess pressure to the accumulator
Solution Approach 1:
The patent incorporates a counterbalance valve and accumulator into the hydraulic system to provide beforehand cushioning against excessive pressure buildup. The counterbalance valve is set to open at a predetermined pressure threshold, allowing fluid to be directed to the accumulator when pressure becomes excessive. This protective mechanism prevents damage to the latch and other system components while maintaining the ability to force the latch to move when needed, with the accumulator absorbing the excess pressure energy.
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 flexible and fail-safe mechanism for securing refuse carts, protecting the latching system and carts from damage by adapting to various sizes and positions, ensuring reliable operation across a range of refuse cart types and configurations.
Implementation Method 1
a master cylinder (30) in fluid communication with a slave cylinder (64) by a flexible hose (60) to operate a latch (84) for keeping a refuse cart (98) on a refuse tipper (10)
Implementation Method 2
a roller (38) attached to the rod (34) for following a cam plate (24) as the tipper moves
Implementation Method 3
a spring (42) acting within the cylinder (40) against the rod (34)
Implementation Method 4
a counterbalance valve (44) adapted to control movement of fluid between the accumulator (46) and the cylinder (40) so that fluid is forced through the counterbalance valve into the accumulator if the latch (84) is obstructed
Implementation Method 5
an accumulator (46) adapted to collect, store and release fluid under pressure
Implementation Method 6
fluid forced from the master cylinder extends the latch (84) into a latching position to hold a lower bar (102) on the refuse cart (98)
Data Source
AI summary
Slidably mounted within the cylinder 108 of the accumulator 46 is a piston 48. A spring 50 is positioned behind the piston 48, which biases the piston 48 toward port 56. The portion of the cylinder 108 occupied by spring 50 is vented to the atmosphere by breather 52, which allows air to pass in and out of cylinder 108. As a result of the spring 50 acting on the piston 48, fluid is collected, stored, and released from the cylinder 108 under pressure. It should be understood that the accumulator could collect, store and release fluid under pressure using energy storage devices other than spring 50. For example, the accumulator 46 could be gas.