Dual-Action Grapple Apparatus with Sequential Actuation
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Solution Overview
Problem
Conventional grapple designs compromise on one or more of the characteristics of minimal closing gap, large opening, and minimal overhang, often focusing on minimizing the closing gap, which leads to issues with handling large objects, mechanical wear, and scalability limitations.
Innovation Solution
A dual-action grapple apparatus with a primary and secondary actuator system, where the primary actuator moves the proximal arm portion and the secondary actuator moves the distal arm portion, allowing for sequential movement to achieve optimal grasping and handling of objects of varying sizes while minimizing overhang and reducing mechanical wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single cylinder rotates the grapple to minimize closing gap, then the closing gap between grapple teeth and bucket is reduced, but the overhang in open position becomes excessive
Solution Approach 1:
The grapple arm is divided into two separate movable portions: a proximal arm portion and a distal arm portion. Each portion is controlled by its own actuator, allowing independent movement control. This segmentation enables the proximal portion to control closing gap while the distal portion controls overhang, resolving the contradiction between these two parameters.
2Manufacturing precision
If a mechanical lock system with guide arm and guide pin is used, then the three characteristics are maximized, but mechanical wear increases due to continuous contact
Solution Approach 1:
The mechanical lock system with guide arm and guide pin is replaced with a dual actuator hydraulic system. The primary and secondary actuators provide controlled movement without continuous mechanical contact and rubbing, eliminating the wear problem while maintaining precise positioning capability through hydraulic control.
3Manufacturing precision
If a guide arm mechanical lock is used to control grapple movement, then grapple positioning is improved, but the system cannot handle large objects that prevent rotation from open to closed position
Solution Approach 1:
The grapple system uses two independently controlled actuators that can operate in different sequences and at different speeds. This dynamic control allows the grapple to adapt to various object sizes: for large objects, the actuators can move more slowly and coordinate to avoid binding, while for small objects, they can operate more quickly. The sequential movement capability provides the versatility needed to handle different object types without the rigid constraints of a mechanical lock system.
Data Source
AI summary
A grapple apparatus may comprise at least one grapple arm movable between an open and a closed position, and having a proximal arm portion and a distal arm portion. The apparatus may include a primary actuator having extended and retracted conditions to move the proximal arm portion, and a secondary actuator having extended and retracted conditions to move the distal arm portion. The primary actuator may be configured such that an initial rate of movement of the primary actuator from the extended condition toward the retracted condition is slower than an initial rate of movement of the secondary actuator from the extended condition toward the retracted condition to produce substantially complete movement of the distal arm portion of the at least one grapple arm toward the open position before movement of the proximal arm portion toward the open position is initiated.