Foldable Cart Pull Rod Locking for Stepless Height Adjustment
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Solution Overview
Problem
Traditional carts cannot be folded integrally and lack stepless adjustment of pull rods, which are inconvenient for users of varying body forms.
Innovation Solution
A cart design incorporating a pull rod mechanism with telescopically connected main and sub-pipes, a folding bracket mechanism with a four-rod mechanism, and a pull rod locking apparatus featuring a knob with symmetrical sliding rods and a lock block for stepless adjustment, along with a mounting frame and clamping hooks for stable locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a traditional rigid support frame is used, then the cart structure is simple and stable, but the cart cannot be folded and occupies large space in idle state
Solution Approach 1:
The support frame is divided into multiple segments connected by folding brackets, allowing each segment to rotate relative to others. This segmentation enables the frame to collapse into a compact configuration while maintaining structural integrity during use.
Solution Approach 2:
The support frame transitions from a static rigid structure to a dynamic foldable structure through the introduction of folding brackets with rotationally connected rods. This allows the frame to change its configuration between extended and folded states.
2Ease of operation
If elastic convex points are used for locking, then the locking apparatus can lock at several fixed lengths, but it cannot realize stepless locking and is difficult to operate
Solution Approach 1:
The locking mechanism transitions from a static fixed-position system to a dynamic adjustable system. The sliding rod can move continuously along the groove, and the elastic convex point can be positioned at any location on the groove, enabling stepless adjustment of locking length.
Solution Approach 2:
The elastic convex point automatically engages with the groove at any position without requiring manual intervention to clamp or release. The spring-loaded convex point self-adjusts to maintain locking at any selected position along the groove.
3Adaptability or versatility
If the pull rod is made telescopic with fixed locking positions, then it can adapt to different body forms, but it cannot achieve stepless adjustment and has limited adaptability
Solution Approach 1:
The pull rod is segmented into telescopic sections that can extend and retract continuously. The locking mechanism is divided into independent components (sliding rod, elastic convex point, groove) that work together to enable continuous adjustment.
Solution Approach 2:
The locking mechanism allows continuous change in the positional parameter of the elastic convex point along the groove, transforming the discrete fixed-length locking into continuous stepless adjustment of pull rod length.
Data Source
AI summary
A cart includes a pull rod mechanism, a folding bracket mechanism, and a pull rod locking apparatus. The pull rod mechanism includes main and sub-pipes connected telescopically. The folding bracket mechanism includes a bearing frame, connecting rods, and connecting elements. The bearing frame and the connecting rod are rotationally connected to the main pipe. The connecting element is rotationally connected to the bearing frame and connecting rod. The pull rod locking apparatus includes a mounting frame, sliding rods, and a knob. The mounting frame is fixedly connected between two main pipes and is symmetrically provided with two sliding grooves. Two sliding rods are provided and slidably connected in two sliding grooves. The knob includes a lock block circumferentially provided with far and near ends. When the knob is rotated until the far end abuts against sliding rod, an end of the sliding rod tightly abuts and locks the sub-pipe.