Self-Centering Pin Puller for Crane Connectors
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Solution Overview
Problem
Existing pin pullers for heavy machinery, such as mobile lift cranes, require precise machining and additional support frames for accurate centering and force application, which increases complexity and cost, especially when pins are large or in hard-to-reach locations.
Innovation Solution
A pin puller design that eliminates the need for a support frame by using first and second support frame members with linear actuators and a length adjustment device, allowing the pin puller to be self-centering and mounted between connectors without bolting or welding, enabling accurate force application without additional machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a support frame is used for mounting the pin puller to the connector, then the pin puller can be securely mounted and force can be applied, but the connector requires precise machining and additional structure, increasing complexity and size
Solution Approach 1:
The patent extracts the support frame from the connector by mounting the pin puller to the lattice section instead. The connector is reduced to its essential function of joining members, while the pin puller's support structure is separated and attached to the lattice section, eliminating the need for precise machining and additional connector structure.
Solution Approach 2:
The lattice section serves as an intermediary structure that provides the mounting surface for the pin puller. Instead of modifying the connector, the lattice section acts as a mediator that absorbs the mounting requirements, allowing the connector to remain simple and the pin puller to be securely mounted elsewhere.
2Ease of manufacture
If the connector is made larger to accommodate pin puller mounting, then the pin puller can be mounted without precise machining, but the connector size increases beyond what is necessary for connection
Solution Approach 1:
The mounting function is extracted from the connector and relocated to the lattice section. This allows the connector to maintain its minimal necessary size for joining members, while the lattice section provides the additional structure needed for pin puller mounting, eliminating the need to enlarge the connector.
3Ease of operation
If dedicated pin pullers are mounted next to pins during operation, then pin manipulation is facilitated, but the pin puller must be precisely centered with respect to the pin holes, requiring precise machining
Solution Approach 1:
The pin puller is designed to be self-centering through its mounting arrangement on the lattice section. The symmetrical mounting structure and the way the support frame members engage with the lattice section automatically center the pin puller with respect to the pin holes, eliminating the need for precise machining and manual centering adjustments.
4Adaptability or versatility
If portable pin pullers are used that can be mounted at different places, then versatility is improved, but the mounting still requires support frames and precise machining at each location
Solution Approach 1:
The lattice section serves as a universal mounting surface for pin pullers throughout the crane structure. By designing the lattice section with consistent geometry and the pin puller with a standardized mounting interface, the same pin puller design can be mounted at multiple locations without requiring custom support frames or precise machining at each site, achieving versatility through standardization.
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
This design reduces the need for precise machining of connectors, allows for smaller pin puller sizes, and simplifies assembly by enabling self-centering pins and reduced manufacturing costs, while maintaining effective force transmission and alignment.
Implementation Method 1
at least one linear actuator connected to the first and second pins, the at least one linear actuator moveable between i) an extended state wherein the pins are extended all of the way though the holes in the first and second connectors
Implementation Method 2
a length adjustment device comprising first and second spacer plates attached to the first and second support frame members, respectively, and jacking bolts extending between first and second spacer plates and engaged therewith, the length adjustment device configured to adjust the distance between the first and second spacer plates by turning the jacking bolts such that the first support frame member is forced into contact with the first connector and the second support frame member is forced into contact with the second connector
Data Source
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AI summary
A pin puller (150) is mounted between first and second connectors (124,125,135,136,145,146) preferably connectors on a lift crane, each of the connectors having a hole (140) therethrough. The pin puller includes: a) first and second support frame members (160, 162); b) a first pin (142) with a first end located in the hole of the first connector and a second end inside the first support frame member; c) a second pin (144) with a first end located in the hole of the second connector and a second end inside the second support frame member; d) at least one linear actuator (170) connected to the first and second pins; and e) a length adjustment device (180, 181) between the first and second support frame members, with its length adjusted so as to force the first support frame member into contact with the first connector and the second support frame member into contact with the second connector.