Gripper Mechanism Rocker Bogey Torque Absorption

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Solution Overview

Problem

Existing gripper mechanisms in robots face issues with torque-induced stress on linear actuators due to reaction forces from gripped objects, particularly in high-precision applications where fine-pitched threads are prone to wear or binding.

Innovation Solution

The gripper mechanism incorporates a rocker bogey that pivots about a protrusion axis, allowing the linear actuator to rock between sides of the gripper actuator, thereby absorbing and minimizing torque, and includes a carrier with anti-rotation mechanisms and cams to constrain the rocker bogey's motion, preventing unwanted torque transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-precision linear actuators with fine-pitched threads are used, then positioning precision is improved, but the actuators become prone to wear and binding under torque-induced stress

Engineering Contradiction:

Improvegripper positioning precisionVSAvoidlinear actuator reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a rocker bogey as an intermediary component between the linear actuator and the gripper jaw. This rocker bogey absorbs and minimizes torque by allowing controlled pivoting motion, thereby protecting the fine-pitched screw threads from direct torque-induced stress while maintaining precise positioning capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful torque reaction forces into beneficial controlled pivoting motion of the rocker bogey. The torque that would otherwise cause binding and wear in the screw threads is instead utilized to enable the rocker bogey to pivot about its axis, which absorbs the stress and protects the precision threading mechanism

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If a rocker bogey is added to absorb torque, then linear actuator stress is reduced, but device complexity increases

Engineering Contradiction:

Improvelinear actuator stress protectionVSAvoidgripper mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into the rocker bogey component: it serves as both a torque-absorbing mechanism and a motion-constraining element. The rocker bogey combines the functions of torque absorption, pivoting motion, and gripper jaw actuation linkage, thereby reducing overall system complexity despite adding a component

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The rocker bogey is designed as a multi-functional component that simultaneously absorbs torque, allows controlled pivoting motion, and transmits linear actuator motion to the gripper jaw. This universal design approach reduces the need for separate components for each function, offsetting the complexity increase

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 effectively reduces stress on the linear actuator, preventing binding and wear, and allows for precise and reliable operation even with high-precision grippers, enhancing the gripper's ability to handle a wide range of objects.

Implementation Method 1

The linear actuator includes a screw shaft and a drive nut

Methodology Applied

Scientific EffectScrew mechanism: Screw

Implementation Method 2

the rocker bogey is coupled to the drive nut at the protrusion to form a pivot point for the rocker bogey and to enable the rocker bogey to pivot about the protrusion axis when the linear actuator drives the first gripper jaw to move relative to the second gripper jaw

Methodology Applied

Scientific EffectTorque absorption through pivoting:

Data Source

PatentUS20250100163A1Gripper mechanism

Publication Date: 2025.03.27 BOSTON DYNAMICS INC

AI summary

A gripper mechanism includes a pair of gripper jaws, a linear actuator, and a rocker bogey. The linear actuator drives a first gripper jaw to move relative to a second gripper jaw. Here, the linear actuator includes a screw shaft and a drive nut where the drive nut includes a protrusion having protrusion axis expending along a length of the protrusion. The protrusion axis is perpendicular to an actuation axis of the linear actuator along a length of the screw shaft. The rocker bogey is coupled to the drive nut at the protrusion to form a pivot point for the rocker bogey and to enable the rocker bogey to pivot about the protrusion axis when the linear actuator drives the first gripper jaw to move relative to the second gripper jaw.