Gripper Force-Multiplying Mechanism for Compact High-Force Holding
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Solution Overview
Problem
Conventional grippers face a trade-off between increasing gripping force and minimizing weight and size, as larger motors or pistons are required to achieve higher gripping forces, leading to increased size and weight, and they struggle to efficiently transition between low-force jaw movement and high-force gripping regimes.
Innovation Solution
The gripper incorporates a force-multiplying mechanism using a lever or rack and pinion system that redirects piston force to amplify the gripping force over reduced jaw travel, allowing for a stronger hold on the workpiece while maintaining a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the size of the motor or piston is increased to achieve higher gripping force, then the gripping force is improved, but the weight and physical size of the gripper increase
Solution Approach 1:
A force-multiplying mechanism acts as an intermediary between the motor/piston and the jaw, amplifying the force output. The mechanism includes a first lever arm connected to the jaw and a second lever arm connected to the motor/piston, with these lever arms interacting through a linkage system to multiply the input force by a factor greater than one, thereby achieving high gripping force without requiring a large motor or piston
Solution Approach 2:
The force multiplication is achieved by transitioning from direct linear force transmission to a rotational lever system with multiple degrees of freedom. The lever arms rotate about pivot points, allowing force amplification through mechanical advantage ratios determined by the lever arm lengths, effectively utilizing rotational motion to achieve force multiplication in the gripping direction
2Force
If the size of the motor or piston is increased to achieve higher gripping force, then the gripping force is improved, but the physical size of the gripper increases
Solution Approach 1:
The force-multiplying mechanism serves as a compact intermediary system that fits within the existing gripper structure. By using lever arms with pivot points and linkages, the system achieves force amplification without requiring a proportionally larger motor housing or piston cylinder, thus maintaining a compact overall gripper volume while delivering high gripping force
Solution Approach 2:
The lever arms and linkage components of the force-multiplying mechanism are arranged to nest within the existing gripper structure. The mechanism components are positioned such that they occupy minimal additional space, with some components potentially sharing mounting locations or structural elements with existing gripper parts, thereby achieving force multiplication without significantly increasing the gripper's external dimensions
3Force
If conventional grippers are designed for high-force gripping, then gripping force is improved, but they require larger jaw travel distance for low-force movement
Solution Approach 1:
The force-multiplying mechanism dynamically adjusts the mechanical advantage ratio during operation. During the approach phase (low-force regime), the mechanism allows for longer jaw travel to achieve proper positioning. Once contact is made and gripping force is required, the mechanism transitions to a high mechanical advantage state that amplifies force while limiting further jaw travel, thus adapting to the different operational requirements of positioning versus gripping
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 solution enables the gripper to achieve increased gripping force with reduced jaw travel, effectively addressing the size and weight trade-offs of conventional grippers and ensuring a secure hold on workpieces with minimal additional bulk.
Implementation Method 1
The gripper incorporates a force-multiplying mechanism using a lever or rack and pinion system that redirects piston force to amplify the gripping force
Data Source
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AI summary
A gripper (2) for gripping a workpiece (28) includes a jaw assembly (4, 6) having an actuator with a housing (18, 20, 22) and an elongate member axially slidably movable within the housing. A force-multiplying mechanism (203b, 209, 201b) is interconnected between the elongate member and the housing. The force-multiplying mechanism is configured to add a mechanical force to the jaw assembly and thereby increase a gripping force on the workpiece during operation of the gripper.