Hydraulic Jack Safety Mechanism with Rack and Dog Locking
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Solution Overview
Problem
Existing commercial lifting systems face challenges such as shifting lift plates, unreliable locking mechanisms, excessive pivotal travel of hydraulic rams, and difficulties in manufacturing and assembling robust and durable components, particularly in the jack stands and power units used for lifting vehicles.
Innovation Solution
The design incorporates a self-aligning lift plate mechanism, a dual locking mechanism with specific cam angles and heat-treated materials for the locking mechanism, and a safety mechanism using a toothed rack bar and dogs to secure the lift arms, along with improved handle controls and a two-position bridge for enhanced functionality and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional lifting system is used, then the basic lifting function is provided, but the lift plate shifts during lifting and the locking mechanism is unreliable
Solution Approach 1:
The self-aligning mechanism is activated before the lifting operation to ensure the lift plate is properly positioned and aligned with the lift arms at the start of the lifting process, preventing shifts during operation
Solution Approach 2:
A self-aligning mechanism acts as an intermediary between the lift plate and lift arms, automatically adjusting and maintaining proper alignment during the lifting operation to prevent shifting and ensure stability
2Reliability
If a robust locking mechanism is implemented, then reliability is improved, but the manufacturing complexity and assembly difficulty increase
Solution Approach 1:
Specific cam angles are selected and applied to the locking mechanism components to achieve reliable locking function while maintaining manufacturability through optimized geometric parameters
Solution Approach 2:
Heat-treated materials are used in the locking mechanism components to enhance strength and reliability, with the heat treatment process applied after manufacturing to maintain ease of fabrication while achieving the required material properties
3Length of moving object
If the hydraulic ram travels excessively to achieve full lift, then the lifting range is increased, but the pivotal travel and mechanical complexity increase
Solution Approach 1:
Spherical bearing surfaces are incorporated into the lift arm pivots to reduce friction and enable smoother motion, allowing for optimized pivotal travel paths that achieve the required lifting range with reduced mechanical complexity
4Duration of action of stationary object
If durable materials and heat treatment are used, then component durability is improved, but manufacturing time and process complexity increase
Solution Approach 1:
Heat-treated materials are specified for critical components to enhance durability and extend service life, with the heat treatment process integrated into the manufacturing workflow to achieve the required material properties
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 results in a robust, reliable, and durable commercial lifting system with improved manufacturability, self-aligning capabilities, and enhanced safety, allowing for efficient and precise lifting operations with reduced maintenance needs.
Implementation Method 1
The proximal end of each dog has a compression spring for urging the distal end of each dog into the rack bar, for mechanically securing the push bar at a desired position in the tracks.
Implementation Method 2
A hydraulic cylinder is secured at the rearward end of the frame for pushing the lateral push bar forward, and for releasing the lateral push bar rearward along the tracks within the frame.
Data Source
AI summary
A hydraulic floor jack includes a rectangular frame with side flanges and having an extended control handle with a control lever. A pivotal lifting mechanism is mounted on the frame including a pair of parallel lift arms having rearward ends interconnected by a lateral push bar. The forward ends of the lift arms are pivotable upward for lifting a load as the push bar is translated forward within a pair of longitudinal “U” channel tracks attached to the inner side flanges. A hydraulic cylinder is secured at the rearward end of the frame for pushing the lateral push bar forward, and for releasing the lateral push bar rearward along the tracks. The safety mechanism includes a toothed rack bar secured on the vertical wall of the tracks. The lateral push bar has bore holes in the ends thereof. A cylindrical dog is slidably supported within each of the bore holes and has a distal end that is extendable for engaging a tooth of the rack bar. The dogs are biased into the extended position and includes linkage for releasing each dog from the rack bar by actuating the control lever