Jib Connection Structure Asymmetric Pin Locking
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Solution Overview
Problem
Existing jib connection structures fail to stabilize the jib when suspended from a boom leading end, causing it to swing sideways and complicating projection and stowage operations due to uneven pin placement and offset positioning.
Innovation Solution
The jib connection structure features right and left jib base end engagement portions with insertion holes positioned to ensure both pins are locked to the jib connection shafts when the jib is suspended, providing two-point support and preventing sideways swinging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the jib base end engagement portions are formed with different longitudinal dimensions to allow pin insertion during offset placement, then the jib can be connected to the boom leading end, but the jib swings sideways and is not stabilized when suspended
Solution Approach 1:
The patent applies asymmetry by intentionally designing the right and left insertion holes at different positions along the jib connection shaft, creating an asymmetric configuration that ensures both pins are locked when the jib is suspended. This asymmetric hole placement resolves the contradiction by maintaining ease of connection while achieving stability through two-point support.
Solution Approach 2:
The patent resolves the stability issue by transitioning from one-point support to two-point support through strategic placement of insertion holes in the longitudinal dimension. By positioning the holes at different locations along the shaft, the system achieves stable two-point suspension that prevents sideways swinging.
2Device complexity
If only one pin is locked to the jib connection shaft during suspension, then the connection structure is simple, but the jib cannot be stabilized and sideways swinging occurs
Solution Approach 1:
The patent applies segmentation by dividing the support function into two separate pins that lock at different positions on the jib connection shaft. This segmentation creates two distinct support points that together provide stable suspension, resolving the contradiction between structural simplicity and jib stability.
Solution Approach 2:
The insertion holes act as intermediaries that enable the pins to lock at specific positions on the jib connection shaft. By designing these holes at strategic locations, the system achieves two-point support that stabilizes the jib while maintaining connection simplicity.
3Stability of the object's composition
If the insertion holes are positioned to lock both pins when suspended, then the jib is stabilized at two points, but the right and left engagement portions have different longitudinal dimensions
Solution Approach 1:
The patent accepts and utilizes the asymmetric configuration of engagement portions as a deliberate design choice to achieve the primary goal of jib stability. The asymmetry in engagement portion dimensions is a necessary consequence of positioning insertion holes to enable two-point support, resolving the contradiction by prioritizing stability over symmetry.
4Ease of operation
If the jib is placed at offset position during connection, then the pins can be inserted into through holes, but the jib swings sideways when suspended from one point
Solution Approach 1:
The patent applies preliminary action by pre-positioning the insertion holes at specific locations that enable both pins to be inserted during offset placement. This preliminary design of hole positions ensures that when the jib is subsequently suspended, both pins are properly locked, achieving stability without compromising ease of insertion.
Data Source
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AI summary
Provided is a jib connection structure capable of restraining a jib from swinging sideways in a state where the jib is suspended from a boom tip end part. This jib connection structure comprises: jib connection shafts (21, 22) projecting horizontally toward both sides from a boom tip end part (14a); and jib base end engagement parts (31, 32) respectively provided to bifurcated jib base end parts (15a). Each jib base end engagement part (31, 32) is U-shaped into which the jib connection shaft (21, 22) can be fitted, and is provided with an insertion hole (31h, 32h) into which a pin (33, 34) for preventing the jib connection shaft (21, 22) from slipping out is inserted. The insertion hole (32h) in one jib base end engagement part (32) is arranged more toward the outside than a U-shaped bottom part (32b).In a state where a jib (15) is suspended from the boom tip end part (14a), the left and right pins (33, 34) engage with the respective jib connection shafts (21, 22), and the jib (15) is suspended at two points. Thus, the jib (15) is restrained from swinging sideways, and the jib can be projected/retracted easily.