Robot Arm Locking Mechanism for Gravity-Induced Power Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing locking devices for robot arms are ineffective in preventing uncontrolled movement due to gravity during power outages, particularly for robot arms with vertical axes, and do not adequately address sudden motor power interruptions.
Innovation Solution
A locking device comprising a ring, hub, plate, rocker, groove, guide ramp, pin, and return spring that automatically locks the robot arm limbs relative to each other upon power failure, using a rocker mechanism to block rotation and ensure stable positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring-loaded lever with roller bearing against the belt is used to detect belt breakage, then the device can respond to belt breakage, but it is ineffective for sudden motor power interruptions and does not prevent uncontrolled arm movement due to gravity
Solution Approach 1:
The invention extracts the locking function from the drive belt detection mechanism and creates a separate, independent locking device that directly engages with the drive shaft. This separate locking mechanism responds to motor power interruptions by using a rocker arm that detects shaft rotation and automatically engages the locking pin with the guide ramp, providing protection against gravity-induced movement regardless of whether the failure mode is belt breakage or power interruption.
Solution Approach 2:
The invention introduces a rocker arm as an intermediary mechanism between the drive shaft and the locking pin. The rocker arm detects shaft rotation through its interaction with the groove and guide ramp, and this intermediate detection mechanism triggers the locking action. This intermediary allows the system to respond to various failure modes including power interruptions, where the shaft may rotate unexpectedly due to gravity.
2Reliability
If a locking device is added to prevent uncontrolled movement during power outages, then safety and stability are improved, but device complexity increases
Solution Approach 1:
The invention merges the locking mechanism directly into the existing hub structure. The locking pin, groove, and guide ramp are integrated components that work together within the hub assembly, eliminating the need for separate external locking devices. This integration reduces overall system complexity while providing the necessary safety function during power outages.
Solution Approach 2:
The locking device is designed to be self-activating through the rocker arm mechanism. When the drive shaft rotates due to power loss, the rocker arm automatically detects this rotation through its interaction with the groove and guide ramp, and the locking pin is automatically engaged without requiring external control systems, sensors, or additional power. This self-service approach adds safety functionality without proportionally increasing system complexity.
3Reliability
If a locking mechanism is implemented to block rotation during power failure, then uncontrolled movement is prevented, but the device requires automatic release capability when power is restored
Solution Approach 1:
The locking mechanism operates in periodic cycles: during normal operation the locking pin is disengaged allowing free rotation, during power failure the rocker arm activates the locking pin to block rotation, and when power is restored the system automatically returns to the unlocked state. This periodic operation between locked and unlocked states provides both safety during failures and automatic recovery when power returns, without requiring manual intervention.
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
The device effectively prevents uncontrolled movement of robot arm components by locking them in place during power outages, ensuring stability and safety, and can be integrated with various mechanical transmissions, allowing for automatic release when power is restored.
Implementation Method 1
a return spring, acting between the plate and the rocker so as to apply a return force bringing the rocker back to the release position
Implementation Method 2
Articulated industrial robot arms are subject to gravity, and depending on their configuration, a sudden interruption of the power supply to the axis motors can cause uncontrolled arm movement
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a locking device (27) comprising: - a ring (29) having a bore (43), - a hub (31), movable in rotation relative to the ring, - a plate (55), integral with the hub (31), - a rocker (33), movable in rotation between a locking position and a release position, - a groove (35), opening onto the bore (43) and formed in the rocker or the plate, - a guide ramp (37), formed at a periphery of the rocker or the plate, - a pin (39), mounted in the groove to be locked between the bore and the guide ramp when the rocker is in the locking position, and - a return spring (41), acting between the plate and the rocker to return the rocker to the release position.